Identification, expression and phylogenetic analysis of the gene sox9a in the testes of Indian major carp Catla catla throughout a reproductive cycle and in the extragonadal tissues

Abstract

Sox9 is a transcriptional factor which is a member of the sox gene family of SRY-related high mobility group (HMG) box genes. Catla catla like other vertebrates, express sox9a gene mainly in the testes, responsible for the sex determination and male gonadal development. The abundance of the mRNA encoding Sox9a was determined by rtqRT-PCR in the tissues of the testes of catla fish throughout the annual reproductive cycle. The expression of sox9a has seen its peak level during the preparatory and previtellogenic period and the expression was very law during the time of resting period or postvitellogenic period. The expression level was prominent in the vitellogenic period, but it is lesser than preparatory and previtellogenic period. The expression of sox9a in the testes was also expressed in other tissues of brain, kidney, heart, muscle and gill. There was no expression of sox9a in the female gonad. This reveals the significant role of this gene in the testes differentiation and in the different phases of reproductory cycle of C. catla.