Diversity of transactivation regions of DMRT1 in vertebrates.

Background: Doublesex and mab-3 related transcription factor (DMRT) 1, commonly found in all vertebrates, regulates the transcription of genes involved in the masculinization and maintenance of gonadal somatic cells and/or germline cell development. DMRT1 has a DNA-binding domain called the DM domain and a transcription regulatory region. Unlike the former, there is little knowledge about the latter transcription regulatory region. This study aimed to identify the transcription activation regions of DMRT1 from four species: humans and mice (mammals), leopard geckos (reptiles), and medaka (teleost fish), adding perspectives on evolutionary conservation and diversity.

Methods and results: For each species, several expression plasmids of deletion mutants were constructed, and the resultant plasmid and a DMRT1-driven luciferase reporter were co-transfected into cultured cells to measure transactivation ability. The key point of this analysis is that the transactivation ability was normalized by quantifying the expression levels of DMRT1 variants using the HiBiT tag. As a result, two to three transactivation regions were suggested to exist in the C-terminal region of the DM domain in all four species. Among seven regions in DMRT1, the fourth region from the N-terminus contributed to transactivation common to the four species, and the sixth and seventh regions on the C-terminal side differed depending on the species.

Conclusions: These findings indicated that the regions involved in the transactivation ability of DMRT1 could subtly change during evolution, indicating diversity in transactivation domains.