Genome wide analysis of the sox32 gene in germline maintenance and differentiation in leopard coral grouper (Plectropomus leopardus).

The Sox family genes, as a group of transcription factors, are widely expressed in vertebrates and play a critical role in reproduction and development. The present study reported that 26 sox genes were identified from the genome and transcriptome of P. leopardus. The phylogenetic tree construction, chromosome localization, and gene structure analysis were executed to verify the evolutionary relationships, gene duplication, and deletion variations of P. leopardus sox genes in evolution. The sequence alignment revealed the HMG-box domain was highly conserved throughout the Sox gene family. The expression profile showed expression levels of sox genes showed tissue specificity. The dimorphic expression pattern of most sox genes in intersex and adult gonads was also observed, suggesting an important role of sox genes for sex differentiation in P. leopardus. Notably, sox32 was specifically highly expressed in gonadal tissues and might play a novel role within the gonads. The fluorescent in situ hybridization (FISH) showed sox32 mRNA was detected in germ stem cells and oocytes of different stages, and lowly expressed in sertoli cells. In testis, sox32 was not detected in male germ cells. Our results provided new insights into the sox32 that might be involved in gonadal development and differentiation in P. leopardus. To sum up, this study comprehensively analyzed the Sox gene family of P. leopardus and provided new insights into the function of sox genes, which could potentially revolutionize our understanding of the mechanisms of sex determination, sex differentiation, and reproductive development in fish.