Germ cell sexual differentiation requires Nanos2-mediated repression of Dazl in mice [Set 1]

ABSTRACT: In mouse embryos, sex-specific differentiation of primordial germ cells (PGCs) begins with distinct cell cycle regulations: while PGCs in female (XX) gonads enter meiosis, PGCs in male (XY) gonads defer meiosis and arrest cell cycle1,2. The mitotic quiescence in XY gonads requires Nanos2, an evolutionarily conserved RNA-binding protein implicated in RNA degradation3-5; however, underlying mechanisms including the identity of its target mRNAs in vivo remain unknown. Here we show that Nanos2 negatively regulates Dazl (Deleted in azoospermia-like), a germline-specific gene encoding an RNA-binding protein that is implicated in translational control and meiotic initiation6,7. Comprehensive microarray analyses identified Dazl as one of the genes that were up-regulated in Nanos2-deficient XY gonads, but down-regulated in Nanos2-expressing XX gonads. Analysis of a BAC transgenic mouse line, in which the 3’UTR of Dazl can be removed by Flp-Frt recombination system, showed that repression of Dazl is likely achieved by the association of Nanos2 with Dazl’s 3’UTR. Elevated levels of Dazl expression in the transgenic XY PGCs resulted in abnormal progression of cell cycles including meiosis, reminiscent of the phenotype observed in Nanos2-/- XY gonads. This phenotype was suppressed by inhibiting retinoic acid (RA) signaling, suggesting that Nanos2 represses Dazl to prevent RA-induced cell cycle progression in XY PGCs. Furthermore, we show that a part of Nanos2-associated mRNAs, most of which are up-regulated in Nanos2-/- XY gonads, can also associate with Dazl, and that excess Dazl impedes localization of Nanos2 to processing-bodies where RNA degradation takes place, suggesting that repression of Dazl is required for Nanos2 to efficiently degrade its target mRNAs. These data provide the first link between the two RNA-binding proteins that play pivotal roles in sexual differentiation of murine PGCs.

ORGANISM(S): Mus musculus

PROVIDER: GSE56793 | GEO | 2015/12/01

SECONDARY ACCESSION(S): PRJNA244620

REPOSITORIES: GEO