Genomewide identification and analysis of heat-shock proteins 70/110 to reveal their potential functions in Chinese soft-shelled turtle Pelodiscus sinensis .

Heat-shock proteins 70/110 (Hsp70/110) are vital molecular chaperones and stress proteins whose expression and production are generally induced by extreme temperatures or external stresses. The Hsp70/110 family is largely conserved in diverse animals. Although many reports have studied and elaborated on the characteristics of Hsp70/110 in various species, the systematic identification and analysis of Hsp70/110 are still poor in turtles. In this study, a genomewide search was performed, and 18 candidate family genes were identified in Chinese soft-shelled turtle, . These PsHSP70/110 proteins contained the conserved "heat shock protein 70" domain. Phylogenetic analysis of PsHSP70/110 and their homologs revealed evolutionary conservation of Hsp70/110 across different species. Tissue-specific expression analysis showed that these genes were differentially expressed in different tissues of . Furthermore, to examine the putative biological functions of , the dynamic expression of genes was analyzed in the testis of during seasonal spermatogenesis following germ cell apoptosis. Notably, genes such as , , and were significantly upregulated in testes along with a seasonal decrease in apoptosis. Protein interaction prediction revealed that PsHSPA1B-L, PsHSPA2, and PsHSPA8 may interact with each other and participate in the MAPK signaling pathway. Moreover, immunohistochemical analysis showed that PsHSPA1B-L, PsHSPA2, and PsHSPA8 protein expression was associated with seasonal temperature variation. The expression profiling and interaction relationships of the PsHSPA1B-L, PsHSPA2, and PsHSPA8 proteins implied their potential roles in inhibiting the apoptosis of germ cells in . These results provide insights into PsHSP70/110 functions and will serve as a rich resource for further investigation of HSP70/110 family genes in and other turtles.