Expression and functional analysis of cytoplasmic dynein during spermatogenesis in Portunus trituberculatus.

The mechanism of acrosome formation in the crab sperm is a hot topic in crustacean reproduction research. Dynein is a motor protein that performs microtubule-dependent retrograde transport and plays an essential role in spermatogenesis. However, whether cytoplasmic dynein participates in acrosome formation in the crab sperm remains poorly understood. In this study, we cloned the cytoplasmic dynein intermediate chain gene (Pt-DIC) from Portunus trituberculatus testis. Pt-DIC is composed of a p150glued-binding domain, a dynein light chain (DLC)-binding domain, and a dynein heavy chain (DHC)-binding domain. The Pt-DIC gene is widely expressed in different tissues, showing the highest expression in the testis, and it is expressed in different stages of spermatid development, indicating important functions in spermatogenesis. We further observed the colocalization of Pt-DIC and Pt-DHC, Pt-DHC and tubulin, and Pt-DHC and GM130, and the results indicated that cytoplasmic dynein may participate in nuclear shaping and acrosome formation via vesicle transport. In addition, we examined the colocalization of Pt-DHC and a mitochondrion (MT) tracker and that of Pt-DHC and prohibitin (PHB). The results indicated that cytoplasmic dynein participated in mitochondrial transport and mitochondrial degradation. Taken together, these results support the hypothesis that cytoplasmic dynein participates in acrosome formation, nuclear shaping, and mitochondrial transport during spermiogenesis in P. trituberculatus. This study will provide valuable guidance for the artificial fertilization and reproduction of P. trituberculatus.