The 762nd MIB Seminar
(Joint Usage/Research Center for the Multi-stratified Host Defense System)
[Seminar in English]
Title
A novel nuclear factor plays a crucial role in initiation of meiosis
Speaker
Associate Prof. Kei-ichiro Ishiguro
Institute of Molecular Embryology and Genetics, Kumamoto University
Date
Jan. 17 (Wed), 2018
16：00～17：00
Venue
Seminar Room, Main Building 1F, Medical Institute of Bioregulation
No.26 on the following linked map.
（http://www.kyushu-u.ac.jp/f/30074/Hospital_en-2017.pdf）
Abstract
The switching from mitotic to meiotic cell cycle is a crucial step for reorganization of meiotic chromosome1, 2 in gametogenesis. In mammals, Stimulated by retinoic acid 8 (STRA8) is required for induction of meiosis. Although the significance of STRA8 in initiating meiosis is recognized, the underlying mechanism how STRA8 involves in meiotic initiation has been largely elusive. To elucidate the molecular mechanisms of meiotic initiation, we purified STRA8 protein complex from testes of the genetically engineered STRA8 knockin mice. Mass-spectrometric analysis identified novel factors that are associated with STRA8. Notably, StIP1 (Stra8 interacting protein-1), which is encoded by a previously uncharacterized hypothetical gene, shows germ cell specific expression patterns in both male and female germ cells. Immuno-fluorescent analysis shows that StIP1 protein is co-expressed with STRA8 in a limited population of pre-meiotic germ cells in male and female. Importantly, despite of STRA8 expression, initiation of meiosis is abolished in StIP1 KO mice. Remarkably, expression of meiotic prophase genes is largely impaired in the absence of StIP1, accounting for severe arrest of germ cells before meiosis. These results suggest that StIP1 together with STRA8 plays a crucial role in initiation of meiosis.
Here, we discuss our latest unpublished data on the issues of meiotic initiation and the consequent chromosome reorganization.
References
- Ishiguro, K. et al.
Meiosis-specific cohesin mediates homolog recognition in mouse spermatocytes.
Genes & Dev. 28, 594-607 (2014) - Kim J, Ishiguro K. et al.
Meikin is a conserved regulator of meiosis I specific kinetochore function.
Nature 517, 466-471 (2015)
Contact
Division of Epigenomics and Development, MIB
Hiroyuki SASAKI
Phone：092(642)6759