Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
Development August 1, 2010; 137 (15): 2519-26.

Opposite roles of DMRT1 and its W-linked paralogue, DM-W, in sexual dimorphism of Xenopus laevis: implications of a ZZ/ZW-type sex-determining system.

Yoshimoto S , Ikeda N , Izutsu Y , Shiba T , Takamatsu N , Ito M .

A Y-linked gene, DMY/dmrt1bY, in teleost fish medka and a Z-linked gene, DMRT1, in chicken are both required for male sex determination. We recently isolated a W-linked gene, DM-W, as a paralogue of DMRT1 in Xenopus laevis, which has a ZZ/ZW-type sex-determining system. The DNA-binding domain of DM-W shows high sequence identity with that of DMRT1, but DM-W has no significant sequence similarity with the transactivation domain of DMRT1. Here, we first show colocalization of DM-W and DMRT1 in the somatic cells surrounding primordial germ cells in ZW gonad during sex determination. We next examined characteristics of DM-W and DMRT1 as a transcription factor in vitro. DM-W and DMRT1 shared a DNA-binding sequence. Importantly, DM-W dose-dependently antagonized the transcriptional activity of DMRT1 on a DMRT1-driven luciferase reporter system in 293 cells. We also examined roles of DM-W or DMRT1 in gonadal formation. Some transgenic ZW tadpoles bearing a DM-W knockdown vector had gonads with a testicular structure, and two developed into frogs with testicular gonads. Ectopic DMRT1 induced primary testicular development in some ZW individuals. These observations indicated that DM-W and DMRT1 could have opposite functions in the sex determination. Our findings support a novel model for a ZZ/ZW-type system in which DM-W directs female sex as a sex-determining gene, by antagonizing DMRT1. Additionally, they suggest that DM-W diverged from DMRT1 as a dominant-negative type gene, i.e. as a ;neofunctionalization'' gene for the ZZ/ZW-type system. Finally, we discuss a conserved role of DMRT1 in testis formation during vertebrate evolution.

PubMed ID: 20573695
Article link: Development

Genes referenced: ddx4 dm-w dmrt1 megs pgc

Article Images: [+] show captions

Xenbase: The Xenopus Model Organism Knowledgebase.
Version: 4.14.0
Major funding for Xenbase is provided by grant P41 HD064556