Molecular Cloning and Expression Pattern of <italic>Dmrt1</italic> and Its Expression Change in Sex Reversal in <italic>Pelodiscus sinensis</italic>

Abstract

In many vertebrate species, <italic>Dmrt1</italic> gene is required for male sexual differentiation. In this study, the mRNA and protein expression of <italic>Dmrt1</italic> gene and its cellular localization in gonads of different developmental stages of both sexes were examined to investigate the involvement of <italic>Dmrt1</italic> in sexual differentiation in <italic>Pelodiscus sinensis</italic>. RACE results showed that the complete cDNA sequence of <italic>P. sinensis</italic> <italic>Dmrt1</italic> was composed of 230 bp of 5′ un-translated region, 1072 bp of 3′ un-translated region and 1107 bp of open reading frame, bearing a highly conserved DM domain, which encodes 368 amino acids. Real-Time PCR and immunofluorescence analysis revealed that <italic>Dmrt1</italic> gene initiated expression in male embryonic gonad of stage 16 before gonadal differentiation, prior to <italic>Sox9</italic> and <italic>Amh</italic> gene. During the gonadal development, Dmrt1 protein localized in the nuclei of pre-sertoli cells, however, no Dmrt1 signal was detected in female gonad. Moreover, <italic>Dmrt1</italic> expression was significantly decreased in estrogen-induced male to female sex reversal. Whereas, <italic>Dmrt1</italic> was trigged to express in aromatase inhibitor-induced female to male sex reversal. In conclusion, this study indicates that <italic>Dmrt1</italic> gene is a male-specific gene and participates in the male gonadal development, which is likely to play a key role during primary male sex determination in <italic>P. sinensis</italic>.