2026
30 April, 2026
Cytoplasmic competition between pronuclei supports early embryonic development
In mammalian zygotes, maternal and paternal genomes are enclosed in separate pronuclei. Here, we show that these pronuclei compete for limited cytoplasmic factors, which constrains nuclear size and maintains proper epigenetic states. When both genomes are combined into a single pronucleus, this competition is lost, leading to nuclear enlargement, epigenetic dysregulation, and reduced developmental potential. These findings demonstrate that pronuclear separation is a fundamental mechanism supporting early embryonic development.
Kyogoku H, Tarama M, Matsuwaka M, Mishina T, Harada A, Nakagawa R, Kumon M, Shimizu Y, Ohkawa Y, Shibata T, Inoue A, Kitajima TS, "Cytoplasmic competition between separate parental pronuclei in zygotes", Nature, doi:10.1038/s41586-026-10417-7.
・Pubmed
・Nature
・Research Briefings in Nature
・News in Science
22 April, 2026
Live imaging of mammalian oocyte formation
In mammals, oocyte formation occurs within the fetus, and thus its process have remained largely elusive. In this study, we have established a technique for ex vivo culture of mouse fetal gonads combined with optical live imaging. Using this technique, we discovered stage-specific membrane blebbing of germ cells. Moreover, we observed no detectable intercellular transfer of organelles, unlike non-mammalian species, suggesting the existence of a mammal-specific mechanism underlying oocyte formation.
Aizawa E, Shimamoto S, Kajikawa E, Hara J, Abe T, Shibuya H, Kitajima TS, "Dynamic blebbing and absence of organelle transfer during mouse oocyte formation", The EMBO Journal, doi:10.1038/s44318-026-00780-6.
・Pubmed
・The EMBO Journal
21 April, 2026
Mitotic Spindle: From living and synthetic systems to theory
At Mitotic Spindle: From living and synthetic systems to theory, held in Dubrovnik, Croatia, from April 12 to 15, 2026, Tomoya Kitajima delivered an invited lecture.
10 April, 2026
Welcome party
We held a welcome party to celebrate Tao Pan, Tae Akizuki, and Mizuki Morihashi joining our lab.
click picture to see other pics
2 April, 2026
New members joined
Tao Pan (Postdoctoral Researcher), and Tae Akizuki and Mizuki Morihashi (Trainees; Doctoral Students in the Graduate School of Biostudies at Kyoto University), joined our team in April.
30 March, 2026
RIKEN BAIHO Award
Our team has been awarded the RIKEN BAIHO Award, which is presented to researchers who have made outstanding contributions to research and development support. Congratulations!!
Tomoya Kitajima, Yuanzhuo Zhou, Kohei Asaki, and Hirohisa Kyogoku “Development of technologies to prevent age-associated egg aneuploidy”
click picture to see other pics
24 March, 2026
PhD degree conferred
Yuanzhuo Zhou was awarded a PhD in Life Sciences at the Kyoto University Graduate School Degree Conferral Ceremony. Congratulations!!
・Kyoto University News
click picture to see the enlarged pic
24 March, 2026
Welcome and farewell party
We held a welcome/farewell party and a bowling event to celebrate Hou joining us, Asai and Zhou starting their new jobs, and Wei entering graduate school.
click picture to see other pics
6 February, 2026
MASSIV 1.0
At MASSIV 1.0, held in Vancouver, Canada, from 19 to 22 January, 2026, Tomoya Kitajima delivered an invited lecture, and Kohei Asai presented a poster.
3 February, 2026
A new member joined
Shengqun Hou (Research Associate) joined our lab in February.
23 January, 2026
"Dynamic Reproductive Lifespan" Next Generation Scientist Meeting
Tomoya Kitajima, So Shimamoto, Manami Koshiguchi, Mihoko Fushii, and Remi Kanemu attended the Next Generation Scientist Meeting of Grant-in-Aid for Transformative Research Areas（A) "Dynamic Reproductive Lifespan" held in Kumamoto on 13 January, 2026 and presented their researches. So and Remi won the Best Poster Awards.
click picture to see other pics
23 January, 2026
SOKENDAI Life Science Retreat 2025
Tomoya Kitajima was invited to present our research at SOKENDAI Life Science Retreat 2025 held in Minamitsuru from 8 to 9 January, 2026.
Upcoming Events
12 May, 2026
MAYosis2026
ONLINE
31 May - 3 June, 2026
International Symposium on Chromosome Dynamics： from Structure to Cellular Function
Awaji, JAPAN
9 June - 12 June, 2026
The 59th Annual Meeting of the Japanese Society of Developmental Biologists
Hiroshima, JAPAN
Archive
2025, 2024, 2023, 2022, 2021, 2020, 2019, 2018, 2017, 2016, 2015, 2014, 2013