Basic Information

Academic Degree

• 修士（地球環境科学）(北海道大学)
• 博士（地球環境科学）(北海道大学)

ID,URL

• J-Global ID

  201401090445083892

researchmap URL

• https://researchmap.jp/7000009233

Research

Research Topics, Overview of the research

• Research Topics

  Dosage compensation for X-linked genes in primates

• Overview of the research

  In female mammals, including humans (XX), one of the two X chromosomes undergoes coordinated inactivation early in development to balance gene expression with males (XY). This phenomenon is known as X chromosome inactivation (XCI). We are studying the dynamics and mechanisms of XCI in primates using early embryos and embryonic stem cells of crab-eating macaques.

Research Areas

• Life sciences, Molecular biology

Papers

• Generation of germinal-vesicle oocytes from mouse embryonic stem cells under an ovarian soma-free condition

  Yoshiaki Nosaka; Masahiro Nagano; Yukihiro Yabuta; Baku Nakakita; So I. Nagaoka; Ikuhiro Okamoto; Hiromichi Sasada; Ken Mizuta; Fumiya Umemura; Hiroto Kuma; Yasushi Okochi; Yoshitaka Katou; Bernard de Massy; Azusa Inoue; Akihito Horie; Masaki Mandai; Hiroshi Ohta; Mitinori Saitou

  Developmental Cell, Jun. 2025

  
• Generation of functional oocytes from male mice in vitro.

  Kenta Murakami; Nobuhiko Hamazaki; Norio Hamada; Go Nagamatsu; Ikuhiro Okamoto; Hiroshi Ohta; Yoshiaki Nosaka; Yukiko Ishikura; Tomoya S Kitajima; Yuichiro Semba; Yuya Kunisaki; Fumio Arai; Koichi Akashi; Mitinori Saitou; Kiyoko Kato; Katsuhiko Hayashi

  Nature, 15 Mar. 2023, Peer-reviewed

  
• ヒト多能性幹細胞を用いた始原生殖細胞様細胞の試験管内誘導

  横林 しほり; 佐々木 恒太郎; 中村 友紀; 岡本 郁弘; 薮田 幸宏; 栗本 一基; 大田 浩; 守時 良演; 佐々木 裕子; 中川 誠人; 斎藤 通紀

  日本生化学会大会・日本分子生物学会年会合同大会講演要旨集, Dec. 2015

  
• Induction of fetal meiotic oocytes from embryonic stem cells in cynomolgus monkeys

  Sayuri Gyobu‐Motani; Yukihiro Yabuta; Ken Mizuta; Yoshitaka Katou; Ikuhiro Okamoto; Masanori Kawasaki; Ayaka Kitamura; Tomoyuki Tsukiyama; Chizuru Iwatani; Hideaki Tsuchiya; Taro Tsujimura; Takuya Yamamoto; Tomonori Nakamura; Mitinori Saitou

  The EMBO Journal, 16 Mar. 2023, Peer-reviewed

  
• Nucleome programming is required for the foundation of totipotency in mammalian germline development

  Masahiro Nagano; Bo Hu; Shihori Yokobayashi; Akitoshi Yamamura; Fumiya Umemura; Mariel Coradin; Hiroshi Ohta; Yukihiro Yabuta; Yukiko Ishikura; Ikuhiro Okamoto; Hiroki Ikeda; Naofumi Kawahira; Yoshiaki Nosaka; Sakura Shimizu; Yoji Kojima; Ken Mizuta; Tomoko Kasahara; Yusuke Imoto; Killian Meehan; Roman Stocsits; Gordana Wutz; Yasuaki Hiraoka; Yasuhiro Murakawa; Takuya Yamamoto; Kikue Tachibana; Jan‐Michel Peters; Leonid A Mirny; Benjamin A Garcia; Jacek Majewski; Mitinori Saitou

  The EMBO Journal, 04 Jul. 2022, Peer-reviewed

  
• The embryonic ontogeny of the gonadal somatic cells in mice and monkeys.

  Kotaro Sasaki; Akiko Oguchi; Keren Cheng; Yasuhiro Murakawa; Ikuhiro Okamoto; Hiroshi Ohta; Yukihiro Yabuta; Chizuru Iwatani; Hideaki Tsuchiya; Takuya Yamamoto; Yasunari Seita; Mitinori Saitou

  Cell reports, 04 May 2021, Peer-reviewed

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• GATA transcription factors, SOX17 and TFAP2C, drive the human germ-cell specification program.

  Yoji Kojima; Chika Yamashiro; Yusuke Murase; Yukihiro Yabuta; Ikuhiro Okamoto; Chizuru Iwatani; Hideaki Tsuchiya; Masataka Nakaya; Tomoyuki Tsukiyama; Tomonori Nakamura; Takuya Yamamoto; Mitinori Saitou

  Life science alliance, May 2021, Peer-reviewed

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• Capturing Human Trophoblast Development with Naive Pluripotent Stem Cells In Vitro

  Shingo Io; Mio Kabata; Yoshiki Iemura; Katsunori Semi; Nobuhiro Morone; Ikuhiro Okamoto; Tomonori Nakamura; Yoji Kojima; Chizuru Iwatani; Hideaki Tsuchiya; Belinda Kaswandy; Eiji Kondoh; Mitinori Saitou; Takuya Yamamoto; Masaki Mandai; Yasuhiro Takashima

  18 Dec. 2020, Peer-reviewed

  
• Induction of the Germ-Cell Fate from Pluripotent Stem Cells in Cynomolgus Monkeys.

  Sakai Y; Nakamura T; Okamoto I; Gyobu-Motani S; Ohta H; Yabuta Y; Tsukiyama T; Iwatani C; Tsuchiya H; Ema M; Morizane A; Takahashi J; Yamamoto T; Saitou M

  Biology of reproduction, Nov. 2019, Peer-reviewed

  
• A symmetric toggle switch explains the onset of random X inactivation in different mammals.

  Mutzel V; Okamoto I; Dunkel I; Saitou M; Giorgetti L; Heard E; Schulz EG

  Nature structural & molecular biology, May 2019, Peer-reviewed

  
• Generation of human oogonia from induced pluripotent stem cells in vitro.

  Yamashiro C; Sasaki K; Yabuta Y; Kojima Y; Nakamura T; Okamoto I; Yokobayashi S; Murase Y; Ishikura Y; Shirane K; Sasaki H; Yamamoto T; Saitou M

  Science (New York, N.Y.), Oct. 2018, Peer-reviewed

  
• Combined Immunofluorescence, RNA FISH, and DNA FISH in Preimplantation Mouse Embryos.

  Okamoto I

  Methods in molecular biology (Clifton, N.J.), 2018, Peer-reviewed, Lead author, Last author, Corresponding author

  
• Contribution of epigenetic landscapes and transcription factors to X-chromosome reactivation in the inner cell mass

  Maud Borensztein; Ikuhiro Okamoto; Laurene Syx; Guillaume Guilbaud; Christel Picard; Katia Ancelin; Rafael Galupa; Patricia Diabangouaya; Nicolas Servant; Emmanuel Barillot; Azim Surani; Mitinori Saitou; Chong-Jian Chen; Konstantinos Anastassiadis; Edith Heard

  NATURE COMMUNICATIONS, Nov. 2017, Peer-reviewed

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• Single-cell transcriptome of early embryos and cultured embryonic stem cells of cynomolgus monkeys

  Tomonori Nakamura; Yukihiro Yabuta; Ikuhiro Okamoto; Kotaro Sasaki; Chizuru Iwatani; Hideaki Tsuchiya; Mitinori Saitou

  Scientific Data, Jun. 2017, Peer-reviewed

  
• In vitro expansion of mouse primordial germ cell-like cells recapitulates an epigenetic blank slate.

  Ohta H; Kurimoto K; Okamoto I; Nakamura T; Yabuta Y; Miyauchi H; Yamamoto T; Okuno Y; Hagiwara M; Shirane K; Sasaki H; Saitou M

  The EMBO journal, May 2017, Peer-reviewed

  
• RNA FISH to study zygotic genome activation in early mouse embryos

  Noémie Ranisavljevic; Ikuhiro Okamoto; Edith Heard; Katia Ancelin

  Methods in Molecular Biology, 2017, Peer-reviewed

  
• In Vitro Derivation and Propagation of Spermatogonial Stem Cell Activity from Mouse Pluripotent Stem Cells.

  Ishikura Y; Yabuta Y; Ohta H; Hayashi K; Nakamura T; Okamoto I; Yamamoto T; Kurimoto K; Shirane K; Sasaki H; Saitou M

  Cell reports, Dec. 2016, Peer-reviewed

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• The Germ Cell Fate of Cynomolgus Monkeys Is Specified in the Nascent Amnion.

  Sasaki K; Nakamura T; Okamoto I; Yabuta Y; Iwatani C; Tsuchiya H; Seita Y; Nakamura S; Shiraki N; Takakuwa T; Yamamoto T; Saitou M

  Developmental cell, Oct. 2016, Peer-reviewed

  
• A developmental coordinate of pluripotency among mice, monkeys and humans.

  Nakamura T; Okamoto I; Sasaki K; Yabuta Y; Iwatani C; Tsuchiya H; Seita Y; Nakamura S; Yamamoto T; Saitou M

  Nature, Aug. 2016, Peer-reviewed

  
• Robust In Vitro Induction of Human Germ Cell Fate from Pluripotent Stem Cells.

  Sasaki K; Yokobayashi S; Nakamura T; Okamoto I; Yabuta Y; Kurimoto K; Ohta H; Moritoki Y; Iwatani C; Tsuchiya H; Nakamura S; Sekiguchi K; Sakuma T; Yamamoto T; Mori T; Woltjen K; Nakagawa M; Yamamoto T; Takahashi K; Yamanaka S

  Cell stem cell, Aug. 2015, Peer-reviewed

  
• SC3-seq: a method for highly parallel and quantitative measurement of single-cell gene expression.

  Nakamura T; Yabuta Y; Okamoto I; Aramaki S; Yokobayashi S; Kurimoto K; Sekiguchi K; Nakagawa M; Yamamoto T; Saitou M

  Nucleic acids research, May 2015, Peer-reviewed

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• The Gpr1/Zdbf2 locus provides new paradigms for transient and dynamic genomic imprinting in mammals

  Rachel Duffie; Sophie Ajjan; Maxim V. Greenberg; Natasha Zamudio; Martin Escamilla del Arenal; Julian Iranzo; Ikuhiro Okamoto; Sandrine Barbaux; Patricia Fauque; Deborah Bourc'his

  GENES & DEVELOPMENT, Mar. 2014, Peer-reviewed

  
• The two active X chromosomes in female ESCs block exit from the pluripotent state by modulating the ESC signaling network.

  Schulz EG; Meisig J; Nakamura T; Okamoto I; Sieber A; Picard C; Borensztein M; Saitou M; Blüthgen N; Heard E

  Cell Stem Cell, Feb. 2014, Peer-reviewed

  
• RNAi-Dependent and Independent Control of LINE1 Accumulation and Mobility in Mouse Embryonic Stem Cells (Retracted article. See vol. 9, e1005519, 2015)

  Constance Ciaudo; Florence Jay; Ikuhiro Okamoto; Chong-Jian Chen; Alexis Sarazin; Nicolas Servant; Emmanuel Barillot; Edith Heard; Olivier Voinnet

  PLOS GENETICS, Nov. 2013, Peer-reviewed

  
• Initiation of X chromosome inactivation during early embryogenesis in mice and in humans

  Catherine Patrat; Ikuhiro Okamoto; Edith Heard

  BULLETIN DE L ACADEMIE NATIONALE DE MEDECINE, Mar. 2013, Peer-reviewed

  
• Spatial partitioning of the regulatory landscape of the X-inactivation centre

  Elphege P. Nora; Bryan R. Lajoie; Edda G. Schulz; Luca Giorgetti; Ikuhiro Okamoto; Nicolas Servant; Tristan Piolot; Nynke L. van Berkum; Johannes Meisig; John Sedat; Joost Gribnau; Emmanuel Barillot; Nils Bluethgen; Job Dekker; Edith Heard

  NATURE, May 2012, Peer-reviewed

  
• Eutherian mammals use diverse strategies to initiate X-chromosome inactivation during development (vol 472, pg 370, 2011)

  Ikuhiro Okamoto; Catherine Patrat; Dominique Thepot; Nathalie Peynot; Patricia Fauque; Nathalie Daniel; Patricia Diabangouaya; Jean-Philippe Wolf; Jean-Paul Renard; Veronique Duranthon; Edith Heard

  NATURE, Jun. 2011, Peer-reviewed

  
• Eutherian mammals use diverse strategies to initiate X-chromosome inactivation during development

  Ikuhiro Okamoto; Catherine Patrat; Dominique Thepot; Nathalie Peynot; Patricia Fauque; Nathalie Daniel; Patricia Diabangouaya; Jean-Philippe Wolf; Jean-Paul Renard; Veronique Duranthon; Edith Heard

  NATURE, Apr. 2011, Peer-reviewed

  
• A Strand-Specific Burst in Transcription of Pericentric Satellites Is Required for Chromocenter Formation and Early Mouse Development

  Aline V. Probst; Ikuhiro Okamoto; Miguel Casanova; Fatima El Marjou; Patricia Le Baccon; Genevieve Almouzni

  DEVELOPMENTAL CELL, Oct. 2010, Peer-reviewed

  
• Lessons from comparative analysis of X-chromosome inactivation in mammals

  Ikuhiro Okamoto; Edith Heard

  CHROMOSOME RESEARCH, Jul. 2009, Peer-reviewed

  
• Monomethylation of Histone H4-Lysine 20 Is Involved in Chromosome Structure and Stability and Is Essential for Mouse Development

  Hisanobu Oda; Ikuhiro Okamoto; Niall Murphy; Jianhua Chu; Sandy M. Price; Michael M. Shen; Maria Elena Torres-Padilla; Edith Heard; Danny Reinberg

  MOLECULAR AND CELLULAR BIOLOGY, Apr. 2009, Peer-reviewed

  
• The dynamics of imprinted X inactivation during preimplantation development in mice

  I. Okamoto; E. Heard

  CYTOGENETIC AND GENOME RESEARCH, 2006, Peer-reviewed

  
• Evidence for de novo imprinted X-chromosome inactivation independent of meiotic inactivation in mice

  Okamoto, I; D Arnaud; P Le Baccon; AP Otte; CM Disteche; P Avner; E Heard

  NATURE, Nov. 2005, Peer-reviewed

  
• Initiation of epigenetic reprogramming of the X chromosome in somatic nuclei transplanted to a mouse oocyte

  SQ Bao; N Miyoshi; Okamoto, I; T Jenuwein; E Heard; MA Surani

  EMBO REPORTS, Aug. 2005, Peer-reviewed

  
• Imprinted X-inactivation in extra-embryonic endoderm cell lines from mouse blastocysts

  T Kunath; D Arnaud; GD Uy; L Okamoto; C Chureau; Y Yamanaka; E Heard; RL Gardner; P Avner; J Rossant

  DEVELOPMENT, Apr. 2005, Peer-reviewed

  
• Mammalian X-chromosome inactivation: An epigenetics paradigm

  E Heard; J Chaumeil; O Masui; Okamoto, I

  COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY, 2004, Peer-reviewed

  
• X-chromosome inactivation in mouse embryonic stem cells: Analysis of histone modifications and transcriptional activity using immunofluorescence and FISH

  J Chaumeil; Okamoto, I; E Heard

  CHROMATIN AND CHROMATIN REMODELING ENZYMES, PT B, 2004, Peer-reviewed

  
• Epigenetic dynamics of imprinted X inactivation during early mouse development

  Okamoto, I; AP Otte; CD Allis; D Reinberg; E Heard

  SCIENCE, Jan. 2004, Peer-reviewed

  
• Developmental abnormalities in mouse embryos tetrasomic for chromosome 11: Apparent similarity to embryos functionally disomic for the X chromosome

  H Mizuno; Okamoto, I; N Takagi

  GENES & GENETIC SYSTEMS, Aug. 2002, Peer-reviewed

  
• Integrated kinetics of X chromosome inactivation in differentiating embryonic stem cells

  J Chaumeil; Okamoto, I; M Guggiari; E Heard

  CYTOGENETIC AND GENOME RESEARCH, 2002, Peer-reviewed

  
• X-chromosome inactivation in XX androgenetic mouse embryos surviving implantation

  Okamoto, I; SS Tan; N Takagi

  DEVELOPMENT, Oct. 2000, Peer-reviewed

  
• The X chromosome dosage compensation program during the development of cynomolgus monkeys.

  Ikuhiro Okamoto; Tomonori Nakamura; Kotaro Sasaki; Yukihiro Yabuta; Chizuru Iwatani; Hideaki Tsuchiya; Shin-Ichiro Nakamura; Masatsugu Ema; Takuya Yamamoto; Mitinori Saitou

  Science (New York, N.Y.), 19 Nov. 2021, Peer-reviewed, Lead author, Corresponding author

  

Misc.

• 異種再構成卵巣培養の改良系を用いたヒト雌性生殖細胞のエピゲノムリプログラミングダイナミクスの理解

  横林しほり; 横林しほり; 横林しほり; 北村彩佳; 薮田幸宏; 水田賢; 岡本郁弘; 大田浩; 斎藤通紀; 斎藤通紀; 斎藤通紀

  日本分子生物学会年会プログラム・要旨集(Web), 2024

  
• Generation of human oogonia from induced pluripotent stem cells in vitro

  Chika Yamashiro; Kotaro Sasaki; Yukihiro Yabuta; Yoji Kojima; Tomonori Nakamura; Ikuhiro Okamoto; Shihori Yokobayashi; Yusuke Murase; Yukiko Ishikura; Kenjiro Shirane; Hiroyuki Sasaki; Takuya Yamamoto; Mitinori Saitou

  Obstetrical and Gynecological Survey, 01 Mar. 2019

  
• Establishment of macaque trophoblast stem cell lines derived from cynomolgus monkey blastocysts.

  Shoma Matsumoto; Christopher J Porter; Naomi Ogasawara; Chizuru Iwatani; Hideaki Tsuchiya; Yasunari Seita; Yu-Wei Chang; Ikuhiro Okamoto; Mitinori Saitou; Masatsugu Ema; Theodore J Perkins; William L Stanford; Satoshi Tanaka

  Scientific reports, 22 Apr. 2020

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Presentations

• The X-chromosome dosage compensation program during the development of cynomolgus monkeys

  Ikuhiro Okamoto

  X-chromosome inactivation: New insights on its 60th anniversary

  
• カニクイザルの発生過程におけるX染色体遺伝子量補正プログラム

  岡本郁弘

  日本人類遺伝学会第６７大会, 16 Dec. 2022, Invited

  
• The X chromosome dosage compensation program during the development of cynomolgus monkeys

  Ikuhiro Okamoto

  第45回日本分子生物学会年会, 01 Dec. 2022, Invited

  

Books and Other Publications

• X染色体不活化と疾患ー新たな展開

  Joint work, 霊長類におけるX染色体遺伝子量補正

  医歯薬出版株式会社, Nov. 2022

  

External funds: Kakenhi

• Analysis of early post-implantation development and establishment of physiological ex vivo culture method in primate

  Grant-in-Aid for Transformative Research Areas (B)

  Transformative Research Areas, Section (III)

  Kyoto University

  Tomonori Nakamura

  From 02 Oct. 2020, To 31 Mar. 2023, Project Closed

  霊長類;発生学;scRNA-seq;着床後胚発生;次元の呪い;カニクイザル

  https://kaken.nii.ac.jp/grant/KAKENHI-PLANNED-20H05761/
• Study of X chromosome inactivation in the monkey embryos

  Grant-in-Aid for Scientific Research (C)

  Basic Section 42040:Laboratory animal science-related

  Kyoto University

  ikuhiro okamoto

  From 01 Apr. 2018, To 31 Mar. 2021, Project Closed

  カニクイザル;X染色体の不活性化;ゲノム編集;ノックアウト細胞;X染色体不活性化;XIST RNA;X染色体の再活性化;初期胚;始原生殖細胞

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18K06030/
• The dynamics of X chromosome reactivation in female PGCs

  Grant-in-Aid for Scientific Research (B)

  Kyoto University

  ikuhiro okamoto

  From 01 Apr. 2013, To 31 Mar. 2017, Project Closed

  マウス;X染色体;再活性化;始原生殖細胞;始源生殖細胞;不活性X染色体の再活性化;不活性X染色体;リプログラミング;ゲノムリプログラミング

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-25291076/
• The study of X chromosome inactivation maintenance in primate.

  Grant-in-Aid for Scientific Research (B)

  Basic Section 42040:Laboratory animal science-related

  Kyoto University

  岡本 郁弘

  From 01 Apr. 2022, To 31 Mar. 2027, Granted

  X染色体の不活性化;霊長類;カニクイザル;XIST;SmcHD1

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-22H02539/
• The study of X chromosome inactivation maintenance in primate.

  Grant-in-Aid for Scientific Research (B)

  Basic Section 42040:Laboratory animal science-related

  Kyoto University

  岡本 郁弘

  From 01 Apr. 2024, To 31 Mar. 2027, Granted

  X染色体不活性化の維持;不活性化X染色体の再活性化;X inactivation;XIST;カニクイザル;X染色体の不活性化;SmcHD1;霊長類

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-23K23804/
• マウス初期胚発生における体細胞型複製タイミング制御確立過程の解析

  Grant-in-Aid for Scientific Research (A)

  Medium-sized Section 43:Biology at molecular to cellular levels, and related fields

  Institute of Physical and Chemical Research

  平谷 伊智朗

  From 01 Apr. 2025, To 31 Mar. 2030, Granted

  DNA複製タイミング;ゲノム3次元構造;マウス初期胚;胚性ゲノム活性化（ZGA;1細胞Hi-C;胚性ゲノム活性化（ZGA）

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-25H00982/

Education

Part-time lecturer

• From 21 Jun. 2013, To 21 Jun. 2013

  分子生物学特論

  前期, 北海道大学, 大学院生命科学院
• From 01 Oct. 2018, To 01 Oct. 2018

  大学院特別セミナー　医学特論

  後期, 富山大学, 医学薬学教育部