Genome-Wide Identification, Phylogeny, and Expression Profile of the Dmrt (Doublesex and Mab-3 Related Transcription Factor) Gene Family in Channel Catfish (Ictalurus punctatus)

Abstract

The <i>Dmrt</i> (Doublesex and Mab-3 related transcription factor) gene family is a class of crucial transcription factors characterized by a conserved DM domain related to sex determination and differentiation, which has been systematically described in various teleost fish, but less in channel catfish (<i>Ictalurus punctatus</i>), an important global aquaculture species in the US and China. In this study, seven <i>Dmrt</i> genes from channel catfish genome were identified and analyzed using bioinformatics methods. Seven <i>IpDmrt</i> genes were distributed unevenly across five chromosomes. Synteny analysis revealed that <i>Dmrt1</i>, <i>Dmrt2a</i>, <i>Dmrt2b</i>, <i>Dmrt3</i>, <i>Dmrt4</i>, and <i>Dmrt5</i> were relatively conserved in teleost fish. Tissue distribution analysis showed that <i>IpDmrt1</i>, <i>IpDmrt2b</i>, <i>IpDmrt5</i>, and <i>IpDmrt6</i> exhibited sexually dimorphic expression patterns and, among them, <i>IpDmrt1</i> and <i>IpDmrt6</i> had high expression levels in the testes, while <i>IpDmrt2b</i> and <i>IpDmrt5</i> had more significant expression levels in the ovaries than in other tissues. After 17β-estradiol treatment, <i>IpDmrt2b</i> and <i>IpDmrt5</i> were significantly up regulated, while the expression of <i>IpDmrt1</i> and <i>IpDmrt6</i> was significantly repressed in XY channel catfish ovaries compared with XX channel catfish ovaries. The present study provides a comprehensive insight into the <i>Dmrt</i> gene family of channel catfish. The results suggest that <i>IpDmrt1</i> and <i>IpDmrt6</i> may play an important role in testis differentiation/development, while <i>IpDmrt2b</i> and <i>IpDmrt5</i> are critical in ovary development in this species.