Expression of STRA8 is conserved in therian mammals but expression of CYP26B1 differs between marsupials and mice

Abstract

The first sign of mammalian germ cell sexual differentiation is the initiation of meiosis in females and of mitotic arrest in males. In the mouse, retinoic acid induces ovarian Stra8 expression and entry of germ cells into meiosis. In developing mouse testes, cytochrome P450 family 26, subfamily b, polypeptide 1 (CYP26B1) produced by the Sertoli cells degrades retinoic acid, preventing Stimulated by Retinoic Acid Gene 8 (Stra8), expression and inhibiting meiosis. However, in developing humans, there is no evidence that CYP26B1 acts a meiosis-inhibiting factor. We therefore examined aspects of the retinoic acid/STRA8/CYP26B1 pathway during gonadal development in the tammar wallaby, a marsupia..