Introduction: Encoding an 88 kDa protein with a thioredoxin-like domain at the N-terminal region, ssp411 is predominantly expressed at several specific stages from round spermatids to spermatozoa in the rat testis at both mRNA and protein levels. SSP411 is conserved in many species, and can be localized in the testis and mature sperm of human, mouse, and rat.
Materials and methods: A line of ssp411 knockout mice (ssp411−/−) was introduced. The fecundity of ssp411−/− mice was evaluated by mating test, testis was histologically analyzed, motility, and morphology of sperm was examined, and fertilization capability of ssp411-defect sperms was assessed by ICSI.
Results and discussion: Only ssp411−/− males are sterile. Compared with WT, testicular weights of ssp411−/− males are significantly lower, and many vacuoles exist in seminiferous tubules. The number of caudal sperm of mature ssp411−/− males is significantly decreased, none of sperms exhibited rapid progressive linear motility, and the morphology of most sperm is abnormal. ssp411-defect sperms could fertilize mouse eggs via ICSI normally, but subsequent cleavage of zygote was delayed by 1020 h, which does not affect development of morula and blastocyst. Combined with reports that mRNA of ssp411 exist in zygotes but absent in the oocyte, our data suggests that ssp411 not only involves in male reproduction but also acts as a sperm factor that may activate oocyte cleavage. We are carrying out studies to uncover the mechanism of male sterility caused by ssp411 defect and its role in activation of first cleavage.
02 - 04 Sep 2014
World Congress of Reproductive Biology