TheCaenorhabditis elegansproteasome subunitRPN-12 is required for hermaphrodite germline sex determination and oocyte quality

Background The proteasome is a multi-subunit complex and a major proteolytic machinery in cells. Most subunits are essential for proteasome function, and depletion of individual subunits normally results in lethality. RPN-12/Rpn12/PSMD8 is a lid subunit of the 19S regulatory particle (RP) of the 26S proteasome. Studies inCaenorhabditis elegansdemonstrated that RNAi depletion of RPN-12 does not result in lethality. RPN-12 has not been well studied in higher eukaryotes. In this study, we investigate the biological significance of RPN-12 inC.elegans. Results We found that the null mutantrpn-12(av93) did not cause major impairment of the proteolytic activity of the proteasome. Mostrpn-12(av93) hermaphrodites lack sperm leading to feminization of the germ line that can be partially rescued by mating to males. The lack of sperm phenotype can be suppressed by downregulation of TRA-1, a player in the hermaphrodite germline sex determination pathway. Also,rpn-12(av93) animals show significant nuclear accumulation of the meiotic kinase WEE-1.3, a protein predominantly localized to the perinuclear region. Interestingly, chemical inhibition of the proteasome did not cause nuclear accumulation of WEE-1.3. Conclusions RPN-12 plays a previously unknown role in oogenesis and the germline sex determination pathway inC.eleganshermaphrodites.

Automated summary

Depletion of RPN-12 in C. elegans does not significantly affect the proteolytic activity of the proteasome, but results in feminization of the germ line due to lack of sperm in hermaphrodites. This phenotype can be partially rescued by mating to males, and RPN-12 plays a previously unknown role in oogenesis and the germline sex determination pathway in C. elegans hermaphrodites.