Kai, Toshie(Graduate School of Biostudies, Division of Integrated Life Science) | Activity Database on Education and Research, Kyoto University

Kai, Toshie

Graduate School of Biostudies, Division of Integrated Life Science Professor

Last Updated :2026/07/21

Basic Information

Faculty

Faculty of Science

Email Address

Email Address
kai.toshie.2wkyoto-u.ac.jp

Professional Memberships

日本発生生物学会

日本分子生物学会

日本RNA学会

Academic Degree

23 Mar. 1995
大阪大学修士（理学）

25 Mar. 1998
大阪大学博士（理学）

Academic Resume (Graduate Schools)

大阪大学, 大学院理学研究科生理学専攻博士後期課程, 修了

大阪大学, 大学院理学研究科生理学専攻博士前期課程, 修了

Academic Resume (Undergraduate School/Majors)

大阪大学, 理学部生物学科, 卒業

Research History

From Jun. 2025, To Present
Kyoto University, Graduate School of Biostudies, 教授

From Oct. 2015, To Present
Osaka University Graduate School of Frontier Biosciences, Professor

From Apr. 2025, To Mar. 2026
The University of Osaka, 大阪大学, 総長補佐

From Apr. 2021, To Mar. 2025
Osaka University, Center for Global Initiatives, Director of Student Mobility Unit, 総長補佐

From Jan. 2011, To Sep. 2015
The National University of Singapore, Department of Biological Science, Adjunct Associate Professor

From Oct. 2010, To Sep. 2015
Temasek Lifesciences Laboratory, Senior Principal Investigator

From Feb. 2007, To Dec. 2010
The National University of Singapore, Department of Biological Science, Adjunct Assistant Professor

From Jun. 2005, To Sep. 2010
Temasek Lifesciences Laboratory, Principal Investigator

From Jan. 2001, To Jun. 2005
Carnegie Institution of Washington/Howard Hughes Medical Institute, Department of Embryology, Research Associate

From Jan. 2000, To Dec. 2001
Science and Technology Agency/Carnegie Institution of Washington, Department of Embryology, Long-term overseas researcher

From Oct. 1999, To Dec. 1999
Carnegie Institution of Washington/Howard Hughes Medical Institute, Department of Embryology, Research Associate

ID,URL

J-Global ID
201801005878143531
External link
https://www.lif.kyoto-u.ac.jp/e/research/lab/148/

researchmap URL

https://researchmap.jp/toshie_kai

Last Updated :2026/07/21

Research

Research Areas

Life sciences, Developmental biology

Life sciences, Molecular biology

Papers

Natural variations in small RNA origin loci generate circuit diversity underlying temperature acclimation in Caenorhabditis elegans.
Misaki Okahata; Taichiro Iki; Sawako Yoshina; Yohei Minakuchi; Yukina Mori; Natsumi Sawada; Toru Miura; Toshie Kai; Atsushi Toyoda; Shohei Mitani; Akane Ohta; Atsushi Kuhara
Proceedings of the National Academy of Sciences of the United States of America, 26 May 2026
Access this paper :

Transcriptional repression of reaper by Stand still ensures female germline development in Drosophila
Masaya Matsui; Shinichi Kawaguchi; Toshie Kai
PLOS Genetics, 05 Mar. 2026, Peer-reviewed, Last author, Corresponding author

Squash enables Spindle-E-dependent heterotypic piRNA amplification in the Drosophila ovary
Xin Xu; Taichiro Iki; Shinichi Kawaguchi; Toshie Kai
iScience, Jul. 2026, Last author, Corresponding author

Paralog‐Dependent Specialization of Paf1C Subunit, Ctr9, for Sex Chromosome Gene Regulation and Male Germline Differentiation in Drosophila
Toshie Kai; Jinglan Zheng; Taichiro Iki
Genes to Cells, Sep. 2025, Peer-reviewed, Lead author, Corresponding author

piRNA processing within non‐membrane structures is governed by constituent proteins and their functional motifs
Ritsuko Suyama; Toshie Kai
The FEBS Journal, Jun. 2025, Peer-reviewed, Last author, Corresponding author

Factories without walls: The molecular architecture and functions of non-membrane organelles in small RNA-guided genome protection.
Shinichi Kawaguchi; Wakana Isshiki; Toshie Kai
Biochimica et biophysica acta. General subjects, 03 May 2025, Peer-reviewed, Last author, Corresponding author

In silico screening by AlphaFold2 program revealed the potential binding partners of nuage-localizing proteins and piRNA-related proteins
Shinichi Kawaguchi; Xu Xin; Soga Takashi; Yamaguchi Kenta; Kawasaki Ryuuya; Shimouchi Ryota; Date Susumu; Kai Toshie
eLife, 22 Apr. 2025, Peer-reviewed, Last author, Corresponding author

HemK2 functions for sufficient protein synthesis and RNA stability through eRF1 methylation during Drosophila oogenesis.
Fengmei Xu; Ritsuko Suyama; Toshifumi Inada; Shinichi Kawaguchi; Toshie Kai
Development (Cambridge, England), 15 Jul. 2024, Peer-reviewed, Last author, Corresponding author

Microbes control Drosophila germline stem cell increase and egg maturation through hormonal pathways
Ritsuko Suyama; Nicolas Cetraro; Joanne Y. Yew; Toshie Kai
Communications Biology, 20 Dec. 2023, Peer-reviewed, Last author, Corresponding author

Tejas functions as a core component in nuage assembly and precursor processing in Drosophila piRNA biogenesis.
Yuxuan Lin; Ritsuko Suyama; Shinichi Kawaguchi; Taichiro Iki; Toshie Kai
The Journal of cell biology, 02 Oct. 2023, Peer-reviewed, Last author, Corresponding author

miRNA/siRNA-directed pathway to produce noncoding piRNAs from endogenous protein-coding regions ensures Drosophila spermatogenesis.
Taichiro Iki; Shinichi Kawaguchi; Toshie Kai
Science advances, 21 Jul. 2023, Peer-reviewed, Last author

Nondomain biopolymers: Flexible molecular strategies to acquire biological functions.
Kazuharu Arakawa; Tetsuro Hirose; Toshifumi Inada; Takuhiro Ito; Toshie Kai; Masaaki Oyama; Yukihide Tomari; Takao Yoda; Shinichi Nakagawa
Genes to cells : devoted to molecular & cellular mechanisms, 30 May 2023, Peer-reviewed

Post-Covid International Exchange Through Lateral Cooperation : Osaka University Virtual University Tour as New Practices of Online International Student Recruitment
張希西; エンクトゥルアリウナ; 李明; 甲斐歳惠; 久田均; アンカウィジャヤクレメン
Osaka University Higher Education Studies, Mar. 2023, Peer-reviewed

The Tudor Domain-Containing Protein, Kotsubu (CG9925), Localizes to the Nuage and Functions in piRNA Biogenesis in D. melanogaster.
Lin-Xenia Lim; Wakana Isshiki; Taichiro Iki; Shinichi Kawaguchi; Toshie Kai
Frontiers in molecular biosciences, 2022, Peer-reviewed, Last author, Corresponding author

Drosophila MARF1 ensures proper oocyte maturation by regulating nanos expression.
Kawaguchi S; Ueki M; Kai T
PloS one, 03 Apr. 2020, Peer-reviewed, Last author, Corresponding author

Editorial overview: Stem cells orchestrate oogenesis: a lesson from the fruit fly, Drosophila melanogaster
Ryusuke Niwa; Toshie Kai
Current Opinion in Insect Science, Feb. 2020, Invited

Modulation of Ago2 Loading by Cyclophilin 40 Endows a Unique Repertoire of Functional miRNAs During Sperm Maturation in Drosophila
Taichiro Iki; Moe Takami; Toshie Kai
Cell Reports, 2020, Peer-reviewed, Last author, Corresponding author

Protecting and diversifying the germline
Ryan J. Gleason; Amit Anand; Toshie Kai; Xin Chen
Genetics, 01 Feb. 2018, Peer-reviewed, Invited, Corresponding author

Heterochromatin protein 1a functions for piRNA biogenesis predominantly from pericentric and telomeric regions in Drosophila
Teo, Ryan Yee Wei; An; , Amit; Sridhar, Vishweshwaren; Okamura, Katsutomo; Kai, Toshie
Nature communications, 2018, Peer-reviewed, Last author, Corresponding author

The piRNA pathway is developmentally regulated during spermatogenesis in Drosophila
Emilie Quenerch'du; Amit Anand; Toshie Kai
RNA, Jul. 2016, Peer-reviewed, Last author, Corresponding author

Germline Cells Drive lives : Beyond Birth and Death of Individuals
甲斐歳恵
生産と技術, Apr. 2016, Peer-reviewed, Invited

A piece of the pi(e): The diverse roles of animal piRNAs and their PIWI partners
Robyn S. M. Lim; Toshie Kai
SEMINARS IN CELL & DEVELOPMENTAL BIOLOGY, Dec. 2015, Peer-reviewed, Invited, Last author, Corresponding author

The Tudor domain protein Tapas, a homolog of the vertebrate Tdrd7, functions in the piRNA pathway to regulate retrotransposons in germline of Drosophila melanogaster
Veena S. Patil; Amit Anand; Alisha Chakrabarti; Toshie Kai
BMC BIOLOGY, Oct. 2014, Peer-reviewed, Last author, Corresponding author

Response to Zhang et al
Toshie Kai
The EMBO Journal, 18 Mar. 2014, Peer-reviewed

Analysis of Hydra PIWI proteins and piRNAs uncover early evolutionary origins of the piRNA pathway
Robyn S. M. Lim; Amit Anand; Chiemi Nishimiya-Fujisawa; Satoru Kobayashi; Toshie Kai
DEVELOPMENTAL BIOLOGY, Feb. 2014, Peer-reviewed, Last author, Corresponding author

Polo-mediated phosphorylation of Maelstrom regulates oocyte determination during oogenesis in Drosophila
Jun Wei Pek; Bing Fu Ng; Toshie Kai
DEVELOPMENT, Dec. 2012, Peer-reviewed, Last author, Corresponding author

Isolation of Undifferentiated Female Germline Cells from Adult Drosophila Ovaries.
Lim RS; Osato M; Kai T
Curr. Protoc. Stem Cell Biol., Aug. 2012, Peer-reviewed, Invited, Last author, Corresponding author

Tudor domain proteins in development
Jun Wei Pek; Amit Anand; Toshie Kai
DEVELOPMENT, Jul. 2012, Peer-reviewed, Invited, Last author, Corresponding author

The tudor domain protein Kumo is required to assemble the nuage and to generate germline piRNAs in Drosophila
Amit Anand; Toshie Kai
EMBO JOURNAL, Feb. 2012, Peer-reviewed, Last author, Corresponding author

piRNA pathway and the potential processing site, the nuage, in the Drosophila germline
Jun Wei Pek; Veena S. Patil; Toshie Kai
DEVELOPMENT GROWTH & DIFFERENTIATION, Jan. 2012, Peer-reviewed

DEAD-box RNA helicase Belle/DDX3 and the RNA interference pathway promote mitotic chromosome segregation
Jun Wei Pek; Toshie Kai
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Jul. 2011, Peer-reviewed, Last author, Corresponding author

Non-coding RNAs enter mitosis: functions, conservation and implications
Jun Wei Pek; Toshie Kai
CELL DIVISION, Feb. 2011, Peer-reviewed

A Role for Vasa in Regulating Mitotic Chromosome Condensation in Drosophila
Jun Wei Pek; Toshie Kai
CURRENT BIOLOGY, Jan. 2011, Peer-reviewed

Repression of Retroelements in Drosophila Germline via piRNA Pathway by the Tudor Domain Protein Tejas
Veena S. Patil; Toshie Kai
CURRENT BIOLOGY, Apr. 2010, Peer-reviewed, Last author, Corresponding author

Drosophila Maelstrom Ensures Proper Germline Stem Cell Lineage Differentiation by Repressing microRNA-7
Jun Wei Pek; Ai Khim Lim; Toshie Kai
DEVELOPMENTAL CELL, Sep. 2009, Peer-reviewed, Last author, Corresponding author

piRNAs mediate posttranscriptional retroelement silencing and localization to pi-bodies in the Drosophila germline
Ai Khim Lim; Liheng Tao; Toshie Kai
JOURNAL OF CELL BIOLOGY, Aug. 2009, Peer-reviewed, Last author, Corresponding author

Conserved germline organelle, nuage, serves as site for processing of Piwi-interacting RNAs.
Pek JW; Kai T
Experimental Medicine, Jan. 2009, Peer-reviewed

Unique germ-line organelle, nuage, functions to repress selfish genetic elements in Drosophila melanogaster
Ai Khim Lim; Toshie Kai
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Apr. 2007, Peer-reviewed, Last author, Corresponding author

The expression profile of purified Drosophila germline stem cells
T Kai; D Williams; AC Spradling
DEVELOPMENTAL BIOLOGY, Jul. 2005, Peer-reviewed, Lead author

Germline stem cells and their niches.
Kai T
Tanpakushitsu Kakusan Koso, May 2004, Peer-reviewed

Differentiating germ cells can revert into functional stem cells in Drosophila melanogaster ovaries
T Kai; A Spradling
NATURE, Apr. 2004, Peer-reviewed, Lead author

An empty Drosophila stem cell niche reactivates the proliferation of ectopic cells
TS Kai; A Spradling
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Apr. 2003, Peer-reviewed, Lead author

Multiple mechanisms for degradation of bacteriophage T4 soc mRNA.
Toshie Kai; Tetsuro Yonesaki
Genetics, Jan. 2002

Stem cells find their niche
Allan Spradling; Daniela Drummond-Barbosa; Toshie Kai
Nature, Nov. 2001, Peer-reviewed, Last author

[Discrimination and specific degradation of mRNAs: a new turn with T4 phage gene silencing].
H Ueno; T Yonesaki; T Kai
Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme, Oct. 1999

Gene 61.3 of bacteriophage T4 is the spackle gene.
T Kai; H Ueno; Y Otsuka; W Morimoto; T Yonesaki
Virology, 01 Aug. 1999

Involvement of other bacteriophage T4 genes in the blockade of protein synthesis and mRNA destabilization by a mutation of gene 61. 5.
T Kai; H Ueno; T Yonesaki
Virology, 15 Aug. 1998

Destabilization of bacteriophage T4 mRNAs by a mutation of gene 61.5.
T Kai; H E Selick; T Yonesaki
Genetics, Sep. 1996

Misc.

Non-membranous RNP condensates control the fate of germline cells
須山律子; 甲斐歳惠
実験医学, 2021

HP1a functions to suppress the evolutionarily fixed and telomeric transposons via piRNAs
Amit Anand; Teo Yee Wei; Katsutomo Okamura; Toshie Kai
GENES & GENETIC SYSTEMS, Dec. 2016

Antisense piRNA amplification, but not piRNA production or nuage assembly, requires the Tudor-domain protein Qin Response
Amit Anand; Toshie Kai
EMBO JOURNAL, Mar. 2014, Peer-reviewed

Post-transcriptional retroelement surveillance is mediated by piRNAs in Drosophila germline
Ai Khim Lim; Liheng Tao; Toshie Kai
MECHANISMS OF DEVELOPMENT, Aug. 2009

Presentations

キャリアパス委員会主催ランチタイムセミナー2025
末次正幸; 甲斐歳惠; 鐘巻将人; 佐田亜衣子; 平谷伊智朗; 胡桃坂仁志
第48回日本分子生物学会年会, 03 Dec. 2025, Invited

The Gender Landscape in Academia in Japan and Beyond
Toshie KAI
JSPS Symposium on Promoting Gender Equality, 27 Feb. 2025, Invited

キャリアパス委員会主催ランチタイムセミナー2024
三浦恭子; 甲斐歳惠; 佐田亜衣子; 來生(道下; 江利子; 武部貴則; 胡桃坂仁志
第47回分子生物学会年会, 27 Nov. 2024, Invited

Processing of small RNAs safeguarding the germline genome in the non-membrane structure, nuage
Toshie KAI
[From Innovations to Applications] 20th Anniversary of relations Osaka U- Strasbourg U, 17 Oct. 2024, Invited

グローバル研究時代の人生とキャリアの調和
甲斐歳惠
日本生化学会第64回生命科学夏の学校, 30 Aug. 2024, Invited

キャリアパス委員会主催ランチタイムセミナー2023
甲斐歳惠; 井関祥子; 大川恭行; 鐘巻将人; 胡桃坂仁志
第46回分子生物学会年会, 06 Dec. 2023, Invited

Structure and function of a non-membrane organelle, nuage, in germline cells
甲斐歳惠
33rd Forum in DOJIN, Invited

Molecular basis of nuage organization by Tejas and coordination for piRNA biogenesis in Drosophila
Toshie KAI
2022 EMBO Workshop on PIWI Proteins and piRNAs, 06 Apr. 2022, Invited

piRNAs and PIWI proteins
EMBO Workshop, Invited

Tudor Domain Proteins and Small Interfering RNAs Protects Germline Cells
The International Conference of the Genetics Society of Korea 2017, 27 Oct. 2017, Invited

HP1a は進化的に古いトランスポゾンとテロメア領域にあるトランスポゾンをpiRNA 経路によって抑制する
日本遺伝学会第88回大会, 07 Sep. 2016, Invited

Nuage and piRNAs function for the safeguard of germline genome
Toshie Kai
55th Annual Drosophila Research Conference, 30 Mar. 2014, Invited

Nuage as a potential processing site of piRNAs in germline cells and stem cells
Emilie Quenerch'du; Robyn S. M. Lim; Amit Anand; Toshie Kai
第15回日本RNA学会年会 RNA 海外若手ワークショップ, 25 Jul. 2013, Invited

Piwi proteins and piRNA function in Hydra stem cells
Asia-Pacific Developmental Biology Conference (APDBC 2012), 08 Oct. 2012, Invited

Tudor Domain Proteins and Piwis Function in Nuage for piRNA Amplification in Stem Cells and Germline Cells
Amit Anand; Lim, Robyn S. m; Toshie Kai
ISSCR 2012, 15 Jun. 2012, Invited

Nuage as a processing site of germline piRNA
Conference on Genome Engineering, 20 Jun. 2011, Invited

Nuage: A Potential Site for Processing of Germline piRNA
Toshie Kai
1st Asia-Pacific Drosophila Research Conference (APDRC), 23 May 2011, Invited

Nuage: A Potential Site for Processing of Germline piRNA
Toshie Kai
Keystone Symposia RNA silencing, 23 Mar. 2011, Invited

International Symposium on Epigenetic Modifications of the Genome: Mechanisms and Implications
13 ADNAT Convention, Invited

The biology of nuage: findings dropped from the clouds in germline cells
Toshie Kai
大阪大学生物学科60周年記念シンポジウム, 2009, Invited

第31回日本分子生物学会年会
2008, Invited

シンガポール国立大学DBS
2006

The symposium of Dynamics of Extracellular Environments
The symposium of Dynamics of Extracellular Environments, 2005, Invited

External funds: Kakenhi

非膜オルガネラ・ヌアージュとRNAヘリカーゼによる生殖細胞ゲノム保護機構
Grant-in-Aid for Scientific Research (B)
Basic Section 43010:Molecular biology-related
The University of Osaka
甲斐歳恵
From 01 Apr. 2025, To 31 Mar. 2028, Granted
非ドメイン型タンパク質;非膜オルガネラ;ヌアージュ;piRNA
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-25K02205/

Genetic analysis of nuage formation regulated by non-domain type proteins
Grant-in-Aid for Transformative Research Areas (A)
Transformative Research Areas, Section (III)
The University of Osaka
甲斐歳恵
From 10 Sep. 2021, To 31 Mar. 2026, Granted
非ドメイン型タンパク質;非膜オルガネラ;ヌアージュ;piRNA
https://kaken.nii.ac.jp/grant/KAKENHI-PLANNED-21H05275/

Management of non-domain biopolymer research group
Grant-in-Aid for Transformative Research Areas (A)
Transformative Research Areas, Section (III)
Hokkaido University
中川真一
From 10 Sep. 2021, To 31 Mar. 2026, Granted
非ドメイン型バイオポリマー;非ドメイン型タンパク質;非ドメイン型RNA;ノンコーディングRNA;天然変性タンパク質;相分離;超天然変性タンパク質;ゲノム編集;lncRNA;天然変性領域
https://kaken.nii.ac.jp/grant/KAKENHI-ORGANIZER-21H05273/

Molecular mechanism of piRNA biogenesis and nuage formation involving Tudor domain proteins
Grant-in-Aid for Scientific Research (B)
Basic Section 43010:Molecular biology-related
Osaka University
Toshie KAI
From 01 Apr. 2021, To 31 Mar. 2024, Project Closed
生殖細胞;小分子RNA;piRNA
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-21H02401/

生殖幹細胞の全能性を保障する多階層的な非ゲノム情報の複製機構の解明
Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
Biological Sciences
Osaka University
甲斐歳恵
From 01 Apr. 2020, To 31 Mar. 2022, Discontinued
キイロショウジョウバエ;生殖細胞;転写因子;DamID;HemK2;6mA修飾;エピジェネティックス;生殖幹細胞;全能性;塩基修飾;染色体高次構造
https://kaken.nii.ac.jp/grant/KAKENHI-PUBLICLY-20H05390/

Elucidation of piRNA biogenesis involving Tudor domain proteins
Grant-in-Aid for Scientific Research (B)
Basic Section 43010:Molecular biology-related
Osaka University
Toshie Kai
From 01 Apr. 2018, To 31 Mar. 2021, Project Closed
piRNA;Drosophila meganogaster;germline;生殖細胞;トランスポゾン;Tudor domain;ピンポン増幅
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18H02375/

Molecular mechanism of germline maintenance and differentiation via long-noncoding RNAs
Grant-in-Aid for Scientific Research (B)
Osaka University
TOSHIE KAI
From 01 Apr. 2014, To 31 Mar. 2018, Project Closed
生殖細胞;非コードRNA;発生・分化
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-26291048/

Last Updated :2026/07/21

Administration

School management (title, position)

From 01 Apr. 2026, To 31 Mar. 2028
大学評価委員会点検・評価実行委員会委員

From 01 Apr. 2026, To 31 Mar. 2028
教育研究評議会評議員

Faculty management (title, position)

From 01 Apr. 2026, To 31 Mar. 2027
生命科学研究科副研究科長

From 01 Nov. 2025
将来像検討委員会

From 01 Apr. 2026, To 31 Mar. 2027
リサーチ・フェロー選考委員会　委員

From 01 Apr. 2026, To 31 Mar. 2027
同窓会　理事

From 01 Apr. 2026, To 31 Mar. 2027
人材育成企画室

From 01 Apr. 2026, To 31 Mar. 2027
業績評価委員会　委員長

From 01 Apr. 2026, To 31 Mar. 2027
自己評価委員会　委員長

From 01 Apr. 2026, To 31 Mar. 2027
ダイバーシティ推進委員会　委員

From 01 Apr. 2026, To 31 Mar. 2027
人権委員会　委員長

From 01 Apr. 2026, To 31 Mar. 2027
国際教育委員会　委員

From 01 Apr. 2026, To 31 Mar. 2027
SPFマウス実験室管理委員会

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