Genome-wide identification and expression profile of the sox gene family in different tissues and during embryogenesis in the Pacific white shrimp (Litopenaeus vannamei)

Sox transcription factors play essential roles in a variety of critical physiological processes. Still, members of the sox gene family have not yet been genome-wide identified in shrimps. In this study, a total of five members of the sox gene family were identified from the genome of Pacific white shrimp Litopenaeus vannamei and classified into three subgroups based on the conserved HMG-box domain. Among them, three belong to the SoxB subgroup (one in B1 and two in B2), one in the SoxC subgroup, and one in the SoxE subgroup. The five sox genes had different sex-biased expression in some tissues. Sox21, soxB1, and sox14 had a higher expression in ovary than in testis. In comparison, sox4 had a male-biased specific expression in the gonad, hepatopancreas, gill, and eyestalk. There was no difference in soxE gene expression between testis and ovary. During embryonic development, the expression level of three sox genes (soxB1, sox21, and soxE) was higher in gastrulation stage compared to previous stages, declined in limb bud stage and then increased in intramembrane nauplius stage; the expression of sox4 was detected in blastula stage and continued to increase in the following two stages and then surged in intramembrane nauplius stage; the highest expression of sox14 was in the fertilized egg stage, and the expression level decreased with the development of the embryo. These results suggest that the shrimp sox gene family may be involved in gametogenesis, tridermogenesis, and neurogenesis.