Cutting edge Seminar

 

Speaker:  Seiya Mizuno  (Associate Professor, Laboratory Animal Science, University of Tsukuba)

Title:  Function of the Exocyst Complex in spermatogenesis

Date&Time:  22 Dec.  (Wed.) 2021, 12:00- 13:00

※This seminar can also be attended through ZOOM. Please check the URL on “HIGO Cutting-Edge Seminar” at Moodle.

https://md.kumamoto-u.ac.jp/course/view.php?id=90416

 

Abstract：

The Exocyt Complex is a protein complex consisting of eight EXOC proteins, EXOC1 to EXOC8. Studies using yeast and cultured human cells have shown that the Exocyt complex is involved in “tethering”, an intracellular membrane trafficking event, and regulates cell migration. We have demonstrated that EXOC1 is essential for early embryonic development by mouse forward genetic analysis (Ref.1). In addition, we recently reported the function of EXOC1 in male germ cells (Ref. 2). In humans and mice, during spermatogenesis, differentiating male germ cells form syncytia. This syncytium is formed by incomplete cell division and consists of neighboring cells derived from the same spermatogonial stem cell that are connected to each other via intercellular bridges. In the male germ cell-specific Exoc1 conditional knock-out mice, aggregated spermatocyte syncytia without intercellular bridges were observed. We generated and analyzed genome-edited epitope tag knock-in mice and found that EXOC1 binds and functions with SNARE proteins, STX2 and SNAP23. Furthermore, we found that EXOC1 contributes to the pseudopod formation of spermatogonia by inactivating the Rho family small GTPase Rac1.

 

Reference：

Ref. 1: Peri-implantation lethality in mice carrying megabase-scale deletion on 5qc3.3 is caused by Exoc1 null mutation. Mizuno S., and Takami K., et. al., Sci Rep, 2015, 5:13632.

Ref. 2: EXOC1 plays an integral role in spermatogonia pseudopod elongation and spermatocyte stable syncytium formation in mice. Osawa Y., and Murata K., et. al., Elife, 2021, 10:e59759.