Molecular cloning and characterization of KIFC1-like kinesin gene (es-KIFC1) in the testis of the Chinese mitten crab Eriocheir sinensis

KIFC1 is essential for acrosome biogenesis and nuclear reshaping during the spermiogenesis of mammals. To explore its functions during the same process in the Chinese mitten crab Eriocheir sinensis, we have cloned and sequenced the cDNA of a mammalian KIFC1 homologue (termed es-KIFC1) from the total RNA of the testis. The 2340 bp es-KIFC1 cDNA contained a 102 bp 5′ untranslated region, a 117 bp 3′ untranslated region and a 2121 bp open reading frame. The putative es-KIFC1 protein owns the divergent tail domain, stalk domain and conserved carboxyl motor domain. Protein alignment demonstrated that es-KIFC1 had 36.9%, 37.3%, 36.6%, 37.6%, and 37.5% identity with its homologues in chicken, human, mouse, zebrafish and African clawed frog, respectively. The phylogenetic tree revealed that es-KIFC1 is more related to vertebrate KIFC1 than invertebrate (NCD). Tissue expression analysis showed the presence of es-KIFC1 in the testis, hepatopancreas, gill, muscle and heart. In situ hybridization showed that the es-KIFC1 mRNA was localized in the proacrosomal vesicle and the periphery of the nuclear membrane in early and middle spermatids. In late spermatids and spermatozoa, es-KIFC1 was expressed in the acrosomal tubule and the band between the acrosome and the nucleus. Therefore, es-KIFC1 probably performs critical functions in the spermiogenesis of E.sinensis.