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TANI Tetsuya

    Department of Advanced Bioscience　Lecturer
Last Updated :2024/04/25

Researcher Information

Degree

  • (BLANK)

URL

ORCID ID

J-Global ID

Research Interests

  • 核移植   reprogramming   iPS細胞   in vitro fertilization   cattle   oocyte   クローン   不死化   Developmental Biology   

Research Areas

  • Life sciences / Laboratory animal science
  • Life sciences / Animal production science

Academic & Professional Experience

  • 2008  - 近畿大学農学部 講師
  • 1999 - 2007  Kindai UniversityFaculty of Agriculture

Education

  •        - 1999  Kindai University  Graduate School of Agriculture  畜産学

Association Memberships

  • 日本畜産学会   日本繁殖生物学会   

Published Papers

  • Lanlan Bai; Tetsuya Tani; Takeshi Kobayashi; Ryotaro Nouda; Yuta Kanai; Yusuke Sano; Kazutoshi Takami; Hiroshi Tomita; Eriko Sugano; Taku Ozaki; Tohru Kiyono; Tomokazu Fukuda
    FEBS Open Bio 2024/02 [Refereed]
  • Tetsuya Tani
    PeerJ 2024/01 [Refereed]
  • Aya Sekine; Genta Yasunaga; Soichiro Kumamoto; So Fujibayashi; Izzah Munirah; Lanlan Bai; Tetsuya Tani; Eriko Sugano; Hiroshi Tomita; Taku Ozaki; Tohru Kiyono; Miho Inoue‐Murayama; Tomokazu Fukuda
    Advanced Biology Wiley 2701-0198 2023/12 [Refereed]
     
    Abstract Primary cultured cells cannot proliferate infinite. The overcoming of this limit can be classified as immortalization. Bypass of p16 senescence protein induces efficient immortalization various types of mammalians is previously reported. However, the Cetacea species is not known. Here, that common minke whale‐derived cells can be immortalized with a combination of human genes, mutant cyclin‐dependent kinase 4 (CDK4R24C), cyclin D1, and Telomerase Reverse Transcriptase (TERT) is reported. These results indicate that the function of cell cycle regulators in premature senescence is evolutionarily conserved. This study describes the conserved roles of cell cycle regulators in the immortalization of cells from humans to Cetacea species. Furthermore, using RNA‐seq based on next‐generation sequencing, the gene expression profiles of immortalized cells are compared with parental cells as well as those immortalized with SV40 large T antigen, which is once a popular method for cellular immortalization. The profiling results show that newly established common minke‐whale‐derived immortaliozed cells have completely different profiles from SV40 cells. This result indicates that the expression of mutant CDK4, cyclin D1, and TERT enables to establish immortalized cell lines with different biological nature from SV40 expressing cells.
  • So Fujibayashi; Tohru Kiyono; Yuka Endo; Tetsuya Tani; Haruka Tate; Lanlan Bai; Eriko Sugano; Hiroshi Tomita; Tomokazu Fukuda
    Analytical biochemistry 669 115119 - 115119 2023/03 [Refereed]
     
    Lentivirus is an efficient gene transfer system that is widely used in basic science. We aimed to improve viral titer by applying an ultra-expression vectors to lentiviral packaging. Application of the ultra-expression vectors increased biological titer 4 times for standard preparation. We also evaluated the efficacy of the ultra-expression vectors to relatively longer insert fragments, such as CSII-CMV-CNROE containing 5 genes in multiple cloning sites. Packaging of the ultra-expression vectors showed 3.5 times higher biological titer compared with the original method. Our improved packaging system could be applied to lentivirus to produce higher titers.
  • Masafumi Katayama; Tomokazu Fukuda; Takehito Kaneko; Yuki Nakagawa; Atsushi Tajima; Mitsuru Naito; Hitomi Ohmaki; Daiji Endo; Makoto Asano; Takashi Nagamine; Yumiko Nakaya; Keisuke Saito; Yukiko Watanabe; Tetsuya Tani; Miho Inoue-Murayama; Nobuyoshi Nakajima; Manabu Onuma
    Communications Biology Springer Science and Business Media LLC 5 (1) 1049 - 1049 2022/10 [Refereed]
     
    Abstract The number of endangered avian-related species increase in Japan recently. The application of new technologies, such as induced pluripotent stem cells (iPSCs), may contribute to the recovery of the decreasing numbers of endangered animals and conservation of genetic resources. We established novel iPSCs from three endangered avian species (Okinawa rail, Japanese ptarmigan, and Blakiston’s fish owl) with seven reprogramming factors (M3O, Sox2, Klf4, c-Myc, Nanog, Lin28, and Klf2). The iPSCs are pluripotency markers and express pluripotency-related genes and differentiated into three germ layers in vivo and in vitro. These three endangered avian iPSCs displayed different cellular characteristics even though the same reprogramming factors use. Japanese ptarmigan-derived iPSCs have different biological characteristics from those observed in other avian-derived iPSCs. Japanese ptarmigan iPSCs contributed to chimeras part in chicken embryos. To the best of our knowledge, our findings provide the first evidence of the potential value of iPSCs as a resource for endangered avian species conservation.
  • Ai Orimoto; Masafumi Katayama; Tetsuya Tani; Keiko Ito; Takahiro Eitsuka; Kiyotaka Nakagawa; Miho Inoue-Murayama; Manabu Onuma; Tohru Kiyono; Tomokazu Fukuda
    Biochemical and biophysical research communications 525 (4) 1046 - 1053 2020/05 [Refereed]
     
    The Amami rabbit (Pentagulus furnessi) is a dark brown-furred rabbit classified as an endangered species and only found in the Amami Islands of Japan. They are often called living fossils because they retain primitive characteristics of ancient rabbits that lived approximately 1 million years ago, such as short feet and hind legs and small ears. Although the ancient rabbit has disappeared due to the competition with European rabbit (Oryctolagus cuniculus) in the most of the Asian area, Amami rabbit survived since Amami Islands has isolated from Japan and Taiwan. Although Amari rabbit is one of the protected animals, their population decreases each year due to human activities, such as deforestation and roadkill. In this study, we collected roadkill samples of Amami rabbits and established primary and immortalized fibroblast cell lines. Combined expression of human-derived mutant Cyclin-dependent kinase 4, Cyclin D1, and hTERT allowed us to immortalize fibroblasts successfully in three individuals of Amami rabbits. The immortalized fibroblasts dramatically extended the cell culture period, when it was compared with the cell culture period of wild type cells. Furthermore, the immortalized cells maintained their normal chromosomal pattern (2n = 46). Our results suggest that cellular senescence which mainly regulated by p16-RB signaling pathway is conserved in animal evolution at least from 1 million years ago.
  • Tetsuya Tani; Takahiro Eitsuka; Masafumi Katayama; Takashi Nagamine; Yumiko Nakaya; Hajime Suzuki; Tohru Kiyono; Kiyotaka Nakagawa; Miho Inoue-Murayama; Manabu Onuma; Tomokazu Fukuda
    PloS one 15 (5) e0234054  2020 [Refereed]
     
    [This corrects the article DOI: 10.1371/journal.pone.0221364.].
  • Ndubuisi Machebe; Soichiro Shimizu; Masaki Hata; Kazuki Ohata; Tetsuya Tani; Yoko Kato
    Journal of Mammalian Ova Research 36 33 - 43 2019/04 [Refereed]
  • Tetsuya Tani; Takahiro Eitsuka; Masafumi Katayama; Takashi Nagamine; Yumiko Nakaya; Hajime Suzuki; Tohru Kiyono; Kiyotaka Nakagawa; Miho Inoue-Murayama; Manabu Onuma; Tomokazu Fukuda
    PloS one 14 (8) e0221364  2019 [Refereed]
     
    The Bonin flying fox (Pteropus pselaphon) is one of the most critically endangered species of animals. The number of this species is estimated to be around 150; being classified at the top rank in the list by International Union of Animal Conservation. Our group previously showed that expression of CDK4, CYCLIN D1, and telomerase reverse transcriptase (TERT) efficiently induce immortalization of human, bovine, swine, monkey, and buffalo-derived cells. In this manuscript, we successfully established the primary cells from Bonin flying fox. We introduced CDK4, CYCLIN D1, and TERT into the primary cells. The established cells showed efficient expression of introduced genes at the protein level. Furthermore, the established cells were free from senescence, indicating it reached to immortalization. Moreover, we showed that interspecies somatic cell nuclear transfer of Bonin flying fox derived cell into bovine embryo allowed the development of the embryo to 8 cell stages. Our established cell has the potential to contribute to species conservation.
  • Masafumi Katayama; Takashi Hirayama; Tetsuya Tani; Katsuhiko Nishimori; Manabu Onuma; Tomokazu Fukuda
    JOURNAL OF CELLULAR PHYSIOLOGY WILEY 233 (2) 990 - 1004 0021-9541 2018/02 [Refereed]
     
    Induced pluripotent stem (iPS) cell technology lead terminally differentiated cells into the pluripotent stem cells through the expression of defined reprogramming factors. Although, iPS cells have been established in a number of mammalian species, including mouse, human, and monkey, studies on iPS cells in avian species are still very limited. To establish chick iPS cells, six factors were used within the poly-cistronic reprogramming vector (PB-R6F), containing M3O (MyoD derived transactivation domain fused with Oct3/4), Sox2, Klf4, c-Myc, Lin28, and Nanog. The PB-R6F derived iPS cells were alkaline-phosphatase and SSEA-1 positive, which are markers of pluripotency. Elevated levels of endogenous Oct3/4 and Nanog genes were detected in the established iPS cells, suggesting the activation of the FGF signaling pathway is critical for the pluripotent status. Histological analysis of teratoma revealed that the established chick iPS cells have differentiation ability into three-germ-layer derived tissues. This is the first report of establishment of avian derived iPS cells with a single poly-cistronic transposon based expression system. The establishment of avian derived iPS cells could contribute to the genetic conservation and modification of avian species.
  • Masafumi Katayama; Takashi Hirayama; Tohru Kiyono; Manabu Onuma; Tetsuya Tani; Satoru Takeda; Katsuhiko Nishimori; Tomokazu Fukuda
    JOURNAL OF REPRODUCTION AND DEVELOPMENT SOCIETY REPRODUCTION & DEVELOPMENT-SRD 63 (3) 311 - 318 0916-8818 2017/06 [Refereed]
     
    The cellular conditions required to establish induced pluripotent stem cells (iPSCs), such as the number of reprogramming factors and/or promoter selection, differ among species. The establishment of iPSCs derived from cells of previously unstudied species therefore requires the extensive optimization of programming conditions, including promoter selection and the optimal number of reprogramming factors, through a trial-and-error approach. While the four Yamanaka factors Oct3/4, Sox2, Klf4, and c-Myc are sufficient for iPSC establishment in mice, we reported previously that six reprogramming factors were necessary for the creation of iPSCs from primary prairie vole-derived cells. Further to this study, we now show detailed data describing the optimization protocol we developed in order to obtain iPSCs from immortalized prairie vole-derived fibroblasts Immortalized cells can be very useful tools in the optimization of cellular reprogramming conditions, as cellular senescence is known to dramatically decrease the efficiency of iPSC establishment. The immortalized prairie vole cells used in this optimization were designated K4DT cells as they contained mutant forms of CDK4, cyclin D, and telomerase reverse transcriptase (TERT). We show that iPSCs derived from these immortalized cells exhibit the transcriptional silencing of exogenous reprogramming factors while maintaining pluripotent cell morphology. There were no observed differences between the iPSCs derived from primary and immortalized prairie vole fibroblasts. Our data suggest that cells that are immortalized with mutant CDK4, cyclin D, and TERT provide a useful tool for the determination of the optimal conditions for iPSC establishment.
  • Tetsuya Tani; Yoko Kato
    CELLULAR REPROGRAMMING MARY ANN LIEBERT, INC 19 (2) 95 - 106 2152-4971 2017/04 [Refereed]
     
    For reprogramming a somatic nucleus during mammalian cloning, metaphase of the second meiotic division (MII) oocytes has been widely used as recipient cytoplasm. High activity of maturation-promoting factor (MPF) and mitogen-activated protein kinase (MAPK) is believed to accelerate the remodeling and/or reprogramming of a somatic nucleus introduced into the ooplasm by somatic cell nuclear transfer. We demonstrated previously that the first step in nuclear reprogramming is not directly regulated by MPF and MAPK because activated oocytes in which MPF activity is diminished and MAPK activity is maintained can develop to the blastocyst stage after receiving an M phase somatic nucleus in bovine cloning. In this study, our aim was to test whether MAPK activity is necessary for the first step in nuclear reprogramming and/or chromatin remodeling (phosphorylation of histone H3 at Ser3, trimethylation of histone H3 at Lys 9, and acetylation of histone H3 at Lys14) in bovine somatic cloning. We found that it was not necessary, and neither was MPF activity.
  • Tomokazu Fukuda; Tetsuya Tani; Seiki Haraguchi; Kenichiro Donai; Nobuyoshi Nakajima; Hirohide Uenishi; Takahiro Eitsuka; Makoto Miyagawa; Sanghoun Song; Manabu Onuma; Yumi Hoshino; Eimei Sato; Arata Honda
    JOURNAL OF CELLULAR BIOCHEMISTRY WILEY 118 (3) 537 - 553 0730-2312 2017/03 [Refereed]
     
    In this study, we created porcine-induced pluripotent stem (iPS) cells with the expression of six reprogramming factors (Oct3/4, Klf4, Sox2, c-Myc, Lin28, and Nanog). The resulting cells showed growth dependent on LIF (leukemia inhibitory factor) and expression of multiple stem cell markers. Furthermore, the iPS cells caused teratoma formation with three layers of differentiation and had both active X chromosomes (XaXa). Our iPS cells satisfied the both of important characteristics of stem cells: teratoma formation and activation of both X chromosomes. Injection of these iPS cells into morula stage embryos showed that these cells participate in the early stage of porcine embryogenesis. Furthermore, the RNA-Seq analysis detected that expression levels of endogenous pluripotent related genes, NANOG, SOX2, ZFP42, OCT3/4, ESRRB, and ERAS were much higher in iPS with six factors than that with four reprogramming factors. We can conclude that the expression of six reprogramming factors enables the creation of porcine iPS cells, which is partially close to naive iPS state. J. Cell. Biochem. 118: 537-553, 2017. (c) 2016 Wiley Periodicals, Inc.
  • Tomokazu Fukuda; Tetsuya Tani; Seiki Haraguchi; Kenichiro Donai; Nobuyoshi Nakajima; Hirohide Uenishi; Takahiro Eitsuka; Makoto Miyagawa; Sanghoun Song; Manabu Onuma; Yumi Hoshino; Eimei Sato; Arata Honda
    Journal of Cellular Biochemistry Wiley 118 (3) i - i 0730-2312 2017/03
  • Kenji Ezoe; Akiko Yabuuchi; Tetsuya Tani; Chiemi Mori; Tetsuya Miki; Yuko Takayama; Zeki Beyhan; Yoko Kato; Takashi Okuno; Tamotsu Kobayashi; Keiichi Kato
    PLOS ONE PUBLIC LIBRARY SCIENCE 10 (5) e0126801  1932-6203 2015/05 [Refereed]
     
    Cryopreservation of mature oocytes and embryos has provided numerous benefits in reproductive medicine. Although successful cryopreservation of germinal-vesicle stage (GV) oocytes holds promise for further advances in reproductive biology and clinical embryology fields, reports regarding cryopreservation of immature oocytes are limited. Oocyte survival and maturation rates have improved since vitrification is being performed at the GV stage, but the subsequent developmental competence of GV oocytes is still low. The purpose of this study was to evaluate the effects of supplementation of the maturation medium with cyclic adenosine monophosphate (cAMP) modulators on the developmental competence of vitrified-warmed GV bovine oocytes. GV oocytes were vitrified-warmed and cultured to allow for oocyte maturation, and then parthenogenetically activated or fertilized in vitro. Our results indicate that addition of a cAMP modulator forskolin (FSK) or 3-isobutyl-1-methylxanthine (IBMX) to the maturation medium significantly improved the developmental competence of vitrified-warmed GV oocytes. We also demonstrated that vitrification of GV oocytes led to a decline in cAMP levels and maturation-promoting factor (MPF) activity in the oocytes during the initial and final phases of maturation, respectively. Nevertheless, the addition of FSK or IBMX to the maturation medium significantly elevated cAMP levels and MPF activity during IVM. Taken together, our results suggest that the cryopreservation-associated meiotic and developmental abnormalities observed in GV oocytes may be ameliorated by an artificial increase in cAMP levels during maturation culture after warming.
  • Hiroyuki Hirai; Tetsuya Tani; Nobuko Katoku-Kikyo; Steven Kellner; Peter Karian; Meri Firpo; Nobuaki Kikyo
    STEM CELLS WILEY-BLACKWELL 29 (9) 1349 - 1361 1066-5099 2011/09 [Refereed]
     
    Induced pluripotent stem cells (iPSCs) can be created by reprogramming differentiated cells through introduction of defined genes, most commonly Oct4, Sox2, Klf4, and c-Myc (OSKM). However, this process is slow and extremely inefficient. Here, we demonstrate radical acceleration of iPSC creation with a fusion gene between Oct4 and the powerful transactivation domain (TAD) of MyoD (M(3)O). Transduction of M(3)O as well as Sox2, Klf4, and c-Myc into fibroblasts effectively remodeled patterns of DNA methylation, chromatin accessibility, histone modifications, and protein binding at pluripotency genes, raising the efficiency of making mouse and human iPSCs more than 50-fold in comparison to OSKM. These results identified that one of the most critical barriers to iPSC creation is poor chromatin accessibility and protein recruitment to pluripotency genes. The MyoD TAD has a capability of overcoming this problem. Our approach of fusing TADs to unrelated transcription factors has far-reaching implications as a powerful tool for transcriptional reprogramming beyond application to iPSC technology. STEM CELLS 2011;29:1349-1361
  • Hiroyuki Hirai; Tetsuya Tani; Nobuaki Kikyo
    INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY U B C PRESS 54 (11-12) 1589 - 1596 0214-6282 2010 [Refereed]
     
    Induced pluripotent stem cell (iPSC) technology is a promising approach for converting one type of a differentiated cell into another type of differentiated cell through a pluripotent state as an intermediate step. Recent studies, however, indicate the possibility of directly converting one cell type to another without going through a pluripotent state. This direct reprogramming approach is dependent on a combination of highly potent transcription factors for cell-type conversion, presumably skipping more physiological and multi-step differentiation processes. A trial-and-error strategy is commonly used to screen many candidate transcription factors to identify the correct combination of factors. We speculate, however, that a better understanding of the functional mechanisms of exemplary transcriptional activators will facilitate the identification of novel factor combinations capable of direct reprogramming. The purpose of this review is to critically examine the literature on three highly potent transcriptional activators: the herpes virus protein, VP16; the master regulator of skeletal muscle differentiation, MyoD and the "pioneer" factor for hepatogenesis, FoxA. We discuss the roles of their functional protein domains, interacting partners and chromatin remodeling mechanisms during gene activation to understand how these factors open the chromatin of inactive genes and reset the transcriptional pattern during cell type conversion.
  • Tetsuya Tani; Hiroaki Shimada; Yoko Kato; Yukio Tsunoda
    Cloning and Stem Cells 9 (2) 267 - 280 1536-2302 2007 [Refereed]
     
    Despite the long-held assumption that reprogramming factors are present in mammalian oocytes at the second metaphase stage, the molecular nature of these factors is not known. Here, we demonstrated that oocytes with the potential to reprogram somatic cell nuclei have a unique 23-kDa protein, phosphorylated transcriptionally controlled tumor protein (TCTP). Injection of TCTP double-stranded RNA into germinal vesicle oocytes decreased the potential of nuclear-transferred (NT) oocytes, but not in vitro fertilized oocytes, to develop into blastocysts. Phosphorylated TCTP is considered to facilitate the first step of somatic cell reprogramming. After transfer of blastocysts that developed from NT oocytes fused with cumulus cells in which phosphorylated TCTP peptide was previously incorporated, the recipient pregnancy rate (47%) increased and the abortion rate (13%) decreased. Moreover, all seven cloned calves survived for at least 1 month after parturition, and had no morphologic abnormalities. The present study demonstrated that pretreatment of donor cells with phosphorylated TCTP peptide has a beneficial effect on the potential of bovine somatic cell nuclei to develop into normal cloned calves. Before widespread application of TCTP for bovine cloning, however, a large-scale embryo transfer study using different donor cell lines of various origins is necessary. © Mary Ann Liebert, Inc.
  • Tetsuya Tani; Yoko Kato; Yukio Tsunoda
    FRONTIERS IN BIOSCIENCE FRONTIERS IN BIOSCIENCE INC 12 (1) 2693 - 2705 1093-9946 2007/01 [Refereed]
     
    Nuclear, microtubular dynamics and spindle assembly checkpoint ( SAC) in bovine somatic cell nuclear transfer ( SCNT) oocytes receiving G1/0 or M phase somatic cell nuclei were studied. SCNT oocytes assembled microtubules, however, the spindles were structurally abnormal, including bi- ,tri-polar or elongated spindles with scattered premature chromosome condensation ( PCC) in G1/0 phase nuclei, and some miniature spindles with unaligned chromosomes in M phase nuclei. In contrast, demecolcine-treated SCNT oocytes formed chromosome clusters with membrane protrusion and significantly induced maturation-promoting factor ( MPF) activity elevation ( up to 177%) for 3 hours, indicating that first SAC at second metaphase ( MII) is established upon spindle disruption in SCNT oocytes. After parthenogenetic stimuli, unlike MII oocytes which prevent exit from MII arrest with high MPF activity upon spindle disruption by second SAC, demecolcine-treated SCNT oocytes could not prevent exit from MII arrest with inactivation of MPF activities, whereas MG132-treated SCNT oocytes could persist at MII arrest, indicating that SCNT oocytes lack the ability for second SAC establishment, however, two G1/0 phase nuclei in an ooplasm restored second SAC establishment upon spindle disruption. Furthermore, the developmental potential of demecolcine-treated SCNT oocytes receiving G1/0 phase nuclei to blastocyst stage was not significantly different than untreated SCNT oocytes ( 29% vs 31%). These results indicate that unlike MII oocytes, SCNT oocytes have aberrant spindle morphology and SAC at MII due to insufficient SAC signals from somatic cell nuclei, thus aberrant remodeling has started immediately after somatic cell nuclear transfer and may be responsible for chromosome instability in SCNT embryos as well as the low successful efficiency of cloning.
  • Tetsuya Tani; Hiroaki Shimada; Yoko Kato; Yukio Tsunoda
    Cloning and Stem Cells 8 (1) 61 - 66 1536-2302 2006 [Refereed]
     
    The present study demonstrated that demecolcine treatment for at least 30 min produces a membrane protrusion in metaphase II-stage bovine oocytes. The maternal chromosome mass is condensed within the protrusion, which makes it easy to remove the maternal chromosomes for nuclear transfer (NT). Maturation promoting factor activity, but not mitogen-activated protein kinase activity, increased up to 30% in oocytes during demecolcine treatment. One normal healthy calf was obtained after transfer of four NT blastocysts produced following demecolcine treatment. Demecolcine treatment did not increase the potential of NT oocytes to develop into blastocysts. The present study demonstrated that chemically-assisted removal of chromosomes is effective for bovine cloning. © Mary Ann Liebert, Inc.
  • S Matsushita; T Tani; Y Kato; Y Tsunoda
    ANIMAL REPRODUCTION SCIENCE ELSEVIER SCIENCE BV 84 (3-4) 293 - 301 0378-4320 2004/09 [Refereed]
     
    The present study examined the competence of oocytes from bovine ovaries stored at low temperatures for at least 1 day, which is the necessary time period to complete inspection for bovine spongiform encephalopathy. Storage of ovaries at 10degreesC for 24h did not affect oocyte maturation (68% versus 68%) or the potential of oocytes to develop into day 8 blastocysts after in vitro fertilization (25% versus 27%), parthenogenetic activation (19% versus 25%), or somatic cell nucleus transfer (27% versus 32%) compared with controls. In vitro-fertilized and parthenogenetic oocytes from ovaries stored at 10degreesC for 48h had a significantly decreased maturation rate and developmental potential, but nucleus-transferred oocytes that received cultured cumulus cells did not (27% versus 32%). Thus, bovine ovaries can be stored at 10degreesC for at least 24h without decreasing oocyte maturation competence or the developmental potential of in vitro-fertilized, parthenogenetically activated, and somatic cell nucleus-transferred oocytes, at least to the blastocyst stage. The present study provides valuable information with regard to removing bovine ovaries from abattoirs after testing for bovine spongiforn encephalopathy. (C) 2004 Elsevier B.V. All rights reserved.
  • Y Kato; H Imabayashi; T Mori; T Tani; M Taniguchi; M Higashi; M Matsumoto; A Umezawa; Y Tsunoda
    BIOLOGY OF REPRODUCTION SOC STUDY REPRODUCTION 70 (2) 415 - 418 0006-3363 2004/02 [Refereed]
     
    Recent studies have demonstrated that somatic stem cells have a flexible potential greater than previously expected when they are transplanted into different tissues. On the other hand, recent studies also have revealed that these potentials might occur because of spontaneous cell fusion with recipient cells. The nuclei of somatic cells could have been reprogrammed when they were artificially or spontaneously fused with mouse embryonic stem (ES) cells. The resultant hybrid cells acquired a developmental pluripotency that the original somatic cells did not have but that ES cells did. LaBarge and Blau (Cell 2002; 111: 589-601) demonstrated that adult bone marrow-derived cells contributed to muscle tissue in a stepwise biological progression. This means that bone marrow-derived cells became satellite cells of mononucleate muscle stem cells after the first irradiation-induced damage to the mouse, and after the second irradiation-induced damage, multinucleate myofibers appeared from the bone marrow-derived cells. Considered together, the differentiation potential of the somatic stem cell nucleus itself remains unclear. Although the pluripotency of somatic stem cell populations has been evaluated, the developmental totipotency of the nuclei of somatic stem cells, whether or not they fused with other cells, has not been shown, except in only one study concerning fetal neural cells (never in adult stem cells). Here, we showed the developmental totipotency of adult bovine mesenchymal stem cells by nuclear transfer.
  • Masahiro Kawakami; Tetsuya Tani; Akiko Yabuuchi; Tatsuya Kobayashi; Hiroshi Murakami; Tatsuya Fujimura; Yoko Kato; Yukio Tsunoda
    Cloning and Stem Cells Mary Ann Liebert Inc 5 (4) 379 - 387 1536-2302 2003/12 [Refereed]
  • T Tani; Y Kato; Y Tsunoda
    BIOLOGY OF REPRODUCTION SOC STUDY REPRODUCTION 69 (6) 1890 - 1894 0006-3363 2003/12 [Refereed]
     
    Cloned mammals with normal fertility have been produced by nuclear transfer. Thus, oocyte cytoplasm has the ability to convert differentiated somatic cell nuclei into a state that resembles the conditions that occur at fertilization (nuclear reprogramming). Despite the long-held assumption that reprogramming factors are present in mammalian oocytes, the molecular nature of these factors is not known. The present study demonstrates that the process of nuclear reprogramming is not directly regulated by maturation promoting factor or mitogen-activated protein kinase activity. The potential for nuclear-transferred oocytes to develop to the blastocyst stage was not different when somatic cells at the M phase were fused with oocytes activated with ionomycin and cycloheximide 1-5 h before (12%-22%) but was significantly decreased when oocytes were activated 6 h before (1%). Further molecular studies on the differences between oocytes with and without reprogramming potential are required and will be useful for the identification of reprogramming factors.
  • Masahiro Kawakami; Tetsuya Tani; Xi Jun Yin; Yoko Kato; Yukio Tsunoda
    Journal of Reproduction and Development 48 (4) 409 - 414 0916-8818 2002/12 [Refereed]
     
    The effects of oxygen tension (5% and 20%) during in vitro culture of oocytes and fetal fibroblast cells on the developmental potential of parthenogenetic and nuclear-transferred porcine oocytes were examined. The potential of parthenogenetic oocytes matured and cultured under different oxygen tensions to develop into blastocysts was not significantly different (5 to 16%). The proportions of enucleated oocytes receiving fetal fibroblast cells that developed into blastocysts were significantly lower when somatic cells were cultured under low oxygen tension (2 and 3%) than under high oxygen tension (7%). The effects of oxygen tension during culture of oocytes and somatic cells on the developmental potential of parthenogenetic and nuclear-transferred oocytes is discussed.
  • Xi Jun Yin; Tetsuya Tani; Isao Yonemura; Masahiro Kawakami; Kazunori Miyamoto; Rie Hasegawa; Yoko Kato; Yukio Tsunoda
    Biology of Reproduction Society for the Study of Reproduction 67 (2) 442 - 446 0006-3363 2002 [Refereed]
     
    The present study demonstrated that brief treatment of in vitro-matured porcine oocytes with demecolcine results in a membrane protrusion that contains a condensed chromosome mass, which can be easily removed by aspiration. This simple, chemically assisted method for removing maternal chromosomes enabled the production of a large number of nuclear-transferred porcine eggs. The development of eggs whose chromosomes were removed by this procedure following transfer of somatic cell nuclei to the blastocyst stage was not significantly different among groups activated using different procedures (6% to 11%) and was also not different among donor cells of different origins (3% to 9%), except for cumulus cells (0.4%). After transfer of 180 to 341 nuclear-transferred eggs that received somatic cells to 6 recipients, 2 of the recipients produced 8 healthy cloned piglets from the heart cells of a female pig. The chemically assisted method for removing maternal chromosomes was also effective for bovine and rabbit eggs.
  • A Yabuuchi; T Tani; Y Kato; Y Tsunoda
    JOURNAL OF EXPERIMENTAL ZOOLOGY WILEY-LISS 289 (3) 208 - 212 0022-104X 2001/02 [Refereed]
     
    The in vitro and in vivo developmental potential of nuclear transferred embryos receiving follicular epithelial cells pretreated with spermine (5 and 20 mM), protamine (0.25 and 25 mg/ml), or putrescine (1 and 100 mug/ml) at room and reduced temperatures was examined in the mouse. The pretreated donor cells were first fused with enucleated oocytes, and then nuclei from reconstituted eggs at the two-cell stage were fused with the enucleated fertilized two-cell embryos. The proportion of reconstituted embryos that developed into blastocysts was not significantly different among groups. After transfer to recipients, implantation rates were not different between groups and fetuses were obtained in protamine- and spermine-treated groups as well as in control groups. These results demonstrate that pretreatment of nuclear donor cells with spermine, protamine, or putrescine does not enhance the developmental potential in vitro or in vivo in the mouse. (C) 2001 Wiley-Liss, Inc.
  • T Amano; T Tani; Y Kato; Y Tsunoda
    JOURNAL OF EXPERIMENTAL ZOOLOGY WILEY-LISS 289 (2) 139 - 145 0022-104X 2001/02 [Refereed]
     
    Full-term development occurred when nuclei from mouse embryonic stem (ES) cells, synchronized in metaphase with nocodazole, were fused with enucleated oocytes or nuclei of reconstituted eggs and again fused with the enucleated blastomeres of fertilized two-cell embryos using inactivated Sendai virus. Two surviving male mice were derived from undifferentiated ES cell nuclei, one from single nuclear transfer and another from serial nuclear transfer. Both were noticeably small and died within 24 hr of birth for unknown reasons. These findings demonstrate that nuclear transfer of ES cells using the fusion method produces young, as does the piezoelectric-actuated nuclear transfer. J. Exp. Zool. 289:139-145, 2001. (C) 2001 Wiley-Liss, Inc.
  • T Tani; Y Kato; Y Tsunoda
    BIOLOGY OF REPRODUCTION SOC STUDY REPRODUCTION 64 (1) 324 - 330 0006-3363 2001/01 [Refereed]
     
    We examined the in vitro developmental potential of nonactivated and activated enucleated ova receiving cumulus cells at various stages of the cell cycle. Eleven to 29% of activated ova receiving donor cells stopped developing at the 8-cell stage but 21% to 50% of nonactivated ova receiving donor cells at either the G(0), G(1), G(2), or M phase, or cycling cells developed into blastocysts. One normal calf was born after transferring five blastocysts that had developed from ova receiving donor cells at the M phase. The present study demonstrated that direct exposure of donor chromosomes to nonactivated ovum cytoplasm is effective for somatic cell nucleus reprogramming, and activated ovum cytoplasm does not reprogram the nucleus.
  • XJ Yin; T Tani; Y Kato; Y Tsunoda
    THERIOGENOLOGY ELSEVIER SCIENCE INC 54 (9) 1469 - 1476 0093-691X 2000/12 [Refereed]
     
    The present study determined a suitable parthenogenetic activation procedure for rabbit oocytes and examined the developmental potential of enucleated oocytes receiving cultured cumulus cells. Unfertilized oocytes recovered from superovulated rabbits were activated with one or two sets of electrical pulses, with or without subsequent administration of 6-dimethylaminopurine (6-DMAP). The proportion of oocytes treated with one or two sets of electrical pulses and 6-DMAP that cleaved (87% and 98%, respectively) and developed into blastocysts (77% and 85%, respectively) was significantly higher (P < 0.05) than those activated with electrical pulses alone (30% and 42% for cleavage, 7% and 17% for blastocysts). Cumulus cells separated from ovulated oocytes obtained from mature rabbits were cultured for three to five passages and then induced to quiescence by serum starvation before nuclear transfer. The enucleated oocytes receiving cumulus cells were activated with electrical pulses followed by the addition of 6-DMAP, and cultured in vitro far 5 to 6 d or transferred to pseudopregnant recipient females 1 d after activation. Of 186 nuclear-transferred oocytes, 123 (66%) cleaved and 42 (23%) developed into blastocysts. After transfer of 174 nuclear-transferred oocytes to 8 recipient females, a total of 3 implantation sites were observed in 3 recipient females but no fetuses were obtained. (C) 2000 by Elsevier Science Inc.
  • T Tani; Y Kato; Y Tsunoda
    THERIOGENOLOGY ELSEVIER SCIENCE INC 53 (8) 1623 - 1629 0093-691X 2000/05 [Refereed]
     
    An efficient method for freezing donor cells is necessary when using nucleus transfer of somatic cells for large-scale cloning. In the present study, we developed a method for freezing and thawing bovine cumulus cell-derived cultured cells to be used as nucleus donors. Cumulus cells were obtained from ovaries of living and slaughtered bovine and cultured in vitro. Cumulus cell-derived cultured cells were serum-starved for several days to induce a quiescent state and then frozen at -70 degrees C for at least 2 d. Immediately thereafter or 2 h after thawing, the cells were used as donor cells for nuclear transfer without additional in vitro culture. The fusion rate with recipient cytoplasts was not affected by the cumulus cell source (slaughtered or living) or time after thawing (0 and 2 h). The cleavage rate of frozen-thawed cumulus cell-derived cultured cells from slaughtered cows immediately after thawing (0 h) was highest (97%) and was significantly higher than that of controls (85%) or cells transferred 2 h after thawing (85%). There were no significant differences among any of the groups in the potential of the nuclear transfer embryos to develop into blastocysts (34 vs 44 and 44%, 39 vs 45 and 46%). Thus, storage of bovine cumulus cell-derived cultured cells in the quiescent state at -70 degrees C is effective and might be useful and convenient for large-scale cloning. The maximum storage periods and developmental potential of embryos after such nucleus transfers requires further examination. (C) 2000 by Elsevier Science Inc.
  • BX Nguyen; Y Sotomaru; T Tani; Y Kato; Y Tsunoda
    THERIOGENOLOGY ELSEVIER SCIENCE INC 53 (7) 1439 - 1448 0093-691X 2000/04 [Refereed]
     
    Preservation by vitrification of Day 7 and Day 8 bovine blastocysts derived from nuclear transfer with cumulus cells was compared with preservation of in vitro fertilized blastocysts. In Experiment I, embryos were vitrified in PBS containing 60% ethylene glycol. In Experiment 2, they were vitrified in combination with partial dehydration using a solution of 39% ethylene glycol + 0.7 M sucrose and 8.6% Ficoll. In Experiment 1, survival and hatching rates were 44 and 95% for nuclear transferred embryos, and 78 and 55% for in vitro fertilized embryos, respectively. In Experiment 2, survival and hatching rates were 93 and 95% for nuclear transfer embryos, and 77 and 85% for in vitro fertilized embryos, respectively. It is concluded that Day 7 and Day 8 bovine blastocysts derived from cumulus cells could be cryopreserved without the loss of viability by a simple and efficient method using a combination of partial dehydration and vitrification. (C) 2000 by Elsevier Science Inc.
  • T Amano; K Nakamura; T Tani; Y Kato; Y Tsunoda
    THERIOGENOLOGY ELSEVIER SCIENCE INC 53 (7) 1449 - 1458 0093-691X 2000/04 [Refereed]
     
    The sensitivity of the inner cell mass (ICM) and trophectoderm (TE) of mouse blastocysts to high temperatures was examined. When blastocysts with a diameter of 100 to 120 mu m treated for 15 to 20 min at 45 degrees C were cultured in vitro, the cell number in the ICM did not increase, although that in the TE did increase. After transfer of treated blastocysts to recipients, implantation was not drastically inhibited but no live fetuses were obtained. These results demonstrated that the ICM at the blastocyst stage was more sensitive to high temperature than the TE. ICM clumps or ES cells were injected into blastocysts treated for 20 min at 45 degrees C. After transfer of injected blastocysts to recipients, we obtained mice derived completely from ICM or ES cells as judged by GPI analysis. Since 4 of 7 ES-cell derived mice, but none of the 6 mice derived from the ICM died after birth, an as yet unidentified epigenetic alteration might have occurred during the establishment and/or culture of ES cells. (C) 2000 by Elsevier Science Inc.
  • Y Kato; T Tani; Y Sotomaru; K Kurokawa; JY Kato; H Doguchi; H Yasue; Y Tsunoda
    SCIENCE AMER ASSOC ADVANCEMENT SCIENCE 282 (5396) 2095 - 2098 0036-8075 1998/12 [Refereed]
     
    Eight carves were derived from differentiated cells of a single adult cow, five from cumulus cells and three from oviductal cells out of 10 embryos transferred to surrogate cows (80 percent success). ALL carves were visibly normal, but four died at or soon after birth from environmental causes, and postmortem analysis revealed no abnormality. These results show that bovine cumulus and oviductal epithelial cells of the adult have the genetic content to direct the development of newborn carves.

Books etc

  • 幹細胞・クローン研究プロトコール―再生医学をめざした幹細胞の分離・培養・分化制御から再プログラム化の研究まで (ポストゲノム時代の実験講座)
    谷 哲弥 (Contributor体細胞クローンウシの作製)羊土社 2001/11

MISC

Industrial Property Rights

Research Grants & Projects

  • 日本学術振興会：科学研究費助成事業
    Date (from‐to) : 2024/04 -2027/03 
    Author : 谷 哲弥
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2021/04 -2024/03 
    Author : 福田 智一; 小林 正之; 谷 哲弥
  • 無限分裂する生殖腺体細胞と幹細胞を用いた卵子作製技術の開発
    Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2018/04 -2021/03 
    Author : 福田 智一; 谷 哲弥
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
    Date (from‐to) : 2014/04 -2017/03 
    Author : KATO Yoko; TANI Tetsuya; TAGUCHI Misato
     
    In this study, we examined whether pre-implantation stage embryos in mammals could be freeze-dried like sperm and somatic cells. When mouse blastocysts were freeze-dried, trehalose supplemented medium for freeze-drying and isotonic solution for rehydration were effective for their blastocoele recovery. For porcine blastocysts, no blastocysts recovered their blastocoele after rehydration in any approach.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2014/04 -2017/03 
    Author : TANI Tetsuya; KASHIWAZAKI Naomi; ITO Junya; FUKUDA Tomokazu; FUKUHARA Takeshi
     
    Studies of nuclear reprogramming in somatic cell nuclear transfer (SCNT) and induced pluripotent stem cells (iPSCs) are good model for understanding for cell differentiation and dedifferentiation under epigenetic regulation. Efficiency of iPSCs reprogramming dramatically improved by fusion of specific amino acid transactivation domain and useful for vole and chickene. Reprogramming based on oocyte by SCNT does not required MAPK activity and improved clone embryo development by H3K9 specific demethylase Kdm4d overexpression in oocyte or somatic cell.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
    Date (from‐to) : 2011 -2012 
    Author : TANI Tetsuya
     
    In this research, we found that transcription factor-base reprogramming require strong Oct4 binding to the promoter region. We succeed strong binding Oct4 promoter region and radical acceleration of mouse iPS cell production by chimeric Oct4 with transactivation domain from MyoD and VP16. However, oocyte-base reprogramming by somatic cell nuclear transfer could not accelerated by chimeric Oct4 injection into ooplasm.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
    Date (from‐to) : 2009 -2010 
    Author : TANI Tetsuya
     
    For enhancement of oocyte-base nuclear reprogramming potential of unfertilized oocytes, we injected nuclear reprogramming inducing factors (Oct3/4,sox2,klf4,c-Myc,Nanog,Gadd45a) for iPS cells establishment into pig unfertilized oocytes before nuclear transfer. However over-expressed oocyte of reprogramming inducing factors could not enhanced developmental potential of porcine nuclear transferred oocytes in vitro.
  • 改変未受精卵を用いた体細胞核移植の初期化促進の試み
    住友財団：基礎科学研究助成
    Date (from‐to) : 2008/04 -2009/03 
    Author : 谷 哲弥
  • 未受精卵からの体細胞核初期化因子の同定と体細胞クローン技術への応用
    稲盛財団：研究助成金
    Date (from‐to) : 2008/04 -2009/03 
    Author : 谷 哲弥
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
    Date (from‐to) : 2004 -2006 
    Author : 谷 哲弥
     
    核移植技術を用いた体細胞クローン動物の作出は、未受精卵子の中に含まれると考えられる体細胞核を初期化することができる因子の存在を明らかにした。また、細胞周期制御の観点から核移植卵の正常性を検討した結果、MII期卵が紡錘体阻害剤により活性化されるスピンドルチェックポイントを核移植卵で調べると、未受精卵子の場合と異なり活性化しないことが明らかとなった。 体細胞核の初期化を誘導する可能性のある因子をウシ未受精卵子のプロテオームにより同定した。そのタンパクは、リン酸化されたTCTP(transcriptionally controlled tumor protein)であり、体細胞核移植卵の胚盤胞期への発生率と相関があることから、体細胞核の初期化機構との相関を詳細に調べた。ウシ未成熟卵子に合成RNAおよびdsRNAインジェクションして強制発現させた卵は、MI期で細胞周期を停止させたが、dsRNAにより発現を阻害した卵子は通常にMII期まで達した。dsRNAによりTCTPの発現を阻害した卵を用いて体外受精・体細胞核移植により発生能を調べると体細胞核移植卵のみ発生能は低下した。さらに、予めドナー細胞である体細胞にリン酸化部位を含むTCTPのペプチドをHIV envelop法を用いて取り込ませた後、核移植卵を作成し体外及び体内発生率を検討した。その結果、体外発生能において差が見られなかったが体内発生能において発生率が向上した。すなわち17頭の受胚雌に移植した結果、8頭(47%)が受胎したが、うち1頭(13%)が妊娠51日目に流産した。その他の妊娠雌は、いずれも自然分娩で正常な子ウシを分娩した。ペプチドを導入しない同じ体細胞を用いた場合の核移植卵の体内発生能は、受胎率は31%(4/13)、流産率は50%(2/4)、分娩後1ヶ月目の子ウシの生存率は0%(0/2)であった。このことからリン酸化TCTPペプチドを導入した体細胞を用いることによって正常な体細胞クローンウシの作出率が向上した。
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
    Date (from‐to) : 2001 -2003 
    Author : TSUNODA Yukio; TANI Tetsuya; KATO Yoko
     
    Some of nuclear-transferred oocytes receiving mouse embryonic stem(ES) cells develop into fertile young. Although the developmental potential of nuclear-transferred oocytes that receive ES cells is high compared with those receive somatic cells, a large proportion die at various developmental stages and the rate of neonatal death is high. The present study examined the effect of 1)aggregation of nuclear-transferred oocytes to increase cell numbers, 2)genetic background of ES cells, 3)different nuclear transfer procedures, 4)cell cycle of ES cells, and 5)activation methods on cloning. The following results were obtained. 1)The low potential of nuclear-transferred oocytes with ES cells to develop into young was not due to the lower cell number of nuclear transferred-embryos. 2)The cloning efficiency with hybrid ES cell lines was not superior to that of an inbred ES cell line. 3)The potential of nuclear-transferred oocytes to develop into blastocysts after fusion by Sendai virus was high compared with that after direct injection. 4)The developmental potential of oocytes receiving ES cells at the M phase was higher than that of oocytes receiving ES cells at the G1 phase. Different activation protocols did not affect the potential to develop into blastocysts. Since the developmental potential of nuclear-transferred oocytes to live pups was still low in all group(1 to 4%), further methodological studies to increase the viability of nuclear-transferred oocytes are required.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
    Date (from‐to) : 2000 -2002 
    Author : TSUNODA Yukio; YONEMURA Isao; TANI Tetsuya
     
    The production of cloned mammals by nuclear transfer of somatic cells into eggs in which the chromosomes were removed at the second metaphase stage (MII) is now feasible. The technology has been extended to apply to the genetic improvement of farm animals, rescue of endangered species, and production of transgenic animals for medical use and organ transplantation. The nuclear transfer technique is currently unreliable, however, because the production efficiency of normal offspring is low. The removal of chromosomes from recipient eggs is one of the key factors affecting cloning efficiency. The chromosomes of rabbit, sheep, goat, bovine , and pig eggs are difficult to observe without DNA staining. Thus, the chromosomes in these species are removed mainly by aspirating or pushing out a large volume of cytoplasm underlying the first polar body with or without Hoechst staining. However, such procedures might decrease the viability of enucleated oocytes. The present study demonstrated that brief treatment of in vitro-matured porcine oocytes with demecolcine results in a membrane protrusion that contains a condensed chromosome mass, which can be easily removed by aspiration. This simple chemically-assisted method for removing maternal chromosomes enabled the production of a large number of nuclear-transferred porcine eggs. The development of eggs whose chromosomes were removed by this procedure following transfer of somatic cell nuclei to the blastocyst stage was not significantly different among groups activated using different procedures and was also not different among donor cells of different origins, except for cumulus cells. After transfer of 180 to 341 nuclear-transferred eggs that received somatic cells to 6 recipients, 2 of the recipients produced 8 healthy cloned piglets from the heart cells of a female pig. The chemically-assisted method for removing maternal chromosomes was also effective for bovine and rabbit eggs.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Encouragement of Young Scientists (A)
    Date (from‐to) : 2000 -2001 
    Author : 谷 哲弥
     
    哺乳動物の卵子を用いた核移植の実験において、ドナー細胞とレシピエント未受精卵細胞質の細胞周期の同調が極めて重要とされている。また、体細胞核を用いた核移植において、G0期のドナー細胞をM期の除核したレシピエント卵細胞質に同調及び融合することでクローン個体を作出する事ができる。 そこで、各細胞周期(G0,G1,S、M及びG2期)に同調された細胞をドナーとして用いて核移植を行った。すなわち卵細胞質は、第二減数分裂中期の卵細胞質(M期)とその卵細胞質に活性化刺激を与えた活性化卵子(S期)をレシピエント卵細胞質としてそれぞれドナー細胞を融合し体外発生能を検討した。核移植卵の体外発生成績は、レシピエント卵細胞質に第二減数分裂中期の卵細胞質(M期)を用いた場合、ドナー細胞がS期以外のすべての組み合わせにおいて胚盤胞期までの発生が確認された。また、M期卵細胞質に活性化刺激を与えた活性化卵子(S期)を用いた場合、すべての組み合わせにおいて8細胞期以降への発生は阻害された。 また、ドナー細胞及びレシピエント卵細胞質にM期を用いた組み合わせによって得られた核移植卵を受配雌に移植検査を行った結果、産子を得ることに成功した。これらのことにより、ウシ体細胞核移植においてドナー細胞にG0期を用いることが重要なのではなく、ドナー細胞とレシピエント卵細胞質の細胞周期の組み合わせが重要であることが明らかとなった。また、体細胞核移植には胚性細胞核を用いた核移植とは異なり、M期のレシピエント卵細胞質を用いることが重要であることから体細胞の初期化因子は胚性細胞核因子とは異なることが明らかとなった。
  • Study on somatic nuclear transfer in bovine

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