MilliporeSigma
  • Localization of ubiquitin C-terminal hydrolase L1 in mouse ova and its function in the plasma membrane to block polyspermy.

Localization of ubiquitin C-terminal hydrolase L1 in mouse ova and its function in the plasma membrane to block polyspermy.

The American journal of pathology (2006-10-31)
Satoshi Sekiguchi, Jungkee Kwon, Etsuko Yoshida, Hiroko Hamasaki, Shizuko Ichinose, Makoto Hideshima, Mutsuki Kuraoka, Akio Takahashi, Yoshiyuki Ishii, Shigeru Kyuwa, Keiji Wada, Yasuhiro Yoshikawa
ABSTRACT

Protein degradation is essential for oogenesis and embryogenesis. The ubiquitin-proteasome system regulates many cellular processes via the rapid degradation of specific proteins. Ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) is exclusively expressed in neurons, testis, ovary, and placenta, each of which has unique biological activities. However, the functional role of UCH-L1 in mouse oocytes remains unknown. Here, we report the expression pattern of UCH-L1 and its isozyme UCH-L3 in mouse ovaries and embryos. Using immunocytochemistry, UCH-L1 was selectively detected on the plasma membrane, whereas UCH-L3 was mainly detected in the cytoplasm, suggesting that these isozymes have distinct functions in mouse eggs. To further investigate the functional role of UCH-L1 in mouse eggs, we analyzed the fertilization rate of UCH-L1-deficient ova of gad female mice. Female gad mice had a significantly increased rate of polyspermy in in vitro fertilization assays, although the rate of fertilization did not differ significantly from wild-type mice. In addition, the litter size of gad female mice was significantly reduced compared with wild-type mice. These results may identify UCH-L1 as a candidate for a sperm-oocyte interactive binding or fusion protein on the plasma membrane that functions during the block to polyspermy in mouse oocytes.