Expression Dynamics Indicate Potential Roles of KIF17 for Nuclear Reshaping and Tail Formation during Spermiogenesis in .

Kinesin family member17 (KIF17), a homologous dimer of the kinesin-2 protein family, has important microtubule-dependent and -independent roles in spermiogenesis. Little is known about KIF17 in the mollusk, , a newly developed mariculture species in China. Here, we cloned the open reading frame of and its related gene, , and performed bioinformatics analysis on both. -KIF17 and -ACT are structurally conserved, indicating that they may be functionally conserved. The expression pattern of mRNA performed during spermiogenesis revealed their expression in diverse tissues, with the highest expression level in the coelomic fluid of . The expressions of and mRNA were relatively high during the breeding season (July-September), suggesting that -KIF17/ACT may be involved in spermatogenesis, particularly during spermiogenesis. Further analysis of mRNA via fluorescence in situ hybridization revealed the continuous expression of this mRNA during spermiogenesis, suggesting potential functions in this process. Immunofluorescence showed that -KIF17 co-localized with α-tubulin and migrated from the perinuclear cytoplasm to one side of the spermatid, forming the sperm tail. -KIF17 and -ACT also colocalized. KIF17 may participate in spermiogenesis of , particularly in nuclear reshaping and tail formation by interacting with microtubule structures similar to the manchette. Moreover, -KIF17 with -ACT is also involved in nuclear reshaping and tail formation in the absence of microtubules. This study provides evidence for the role of KIF17 during spermiogenesis and provides theoretical data for studies of the reproductive biology of . These findings are important for spermatogenesis in mollusks.