Chick gonad explant electroporation reveals enhancers for testes determining factor, DMRT1.

Enhancers are key regulatory elements that coordinate precise spatio-temporal gene expression during embryonic development. In this study, we used the chick to investigate the regulatory landscape of the highly conserved transcription factor DMRT1 which is essential for testes development. By performing ATAC-Seq and comparative genomics, we identified two putative enhancers, DMRT1 ROI14 and DMRT1 ROI8, located within intronic regions of DMRT1. To determine whether these two regions are active elements, we developed a Tol2 transposon-based enhancer reporter construct and established a gonad explant electroporation method. We show that while the HSV TK minimal promoter exhibits high levels of basal expression in the gonad, both DMRT1 ROI14 and DMRT1 ROI8 display enhancer activity in male explants only. Overall, this study is the first step towards deciphering the regulatory machinery behind the sex-specific expression of DMRT1.