Retinoic Acid Activates Two Pathways Required for Meiosis in Mice

<div><p>In all sexually reproducing organisms, cells of the germ line must transition from mitosis to meiosis. In mice, retinoic acid (RA), the extrinsic signal for meiotic initiation, activates transcription of <i>Stra8</i>, which is required for meiotic DNA replication and the subsequent processes of meiotic prophase. Here we report that RA also activates transcription of <i>Rec8</i>, which encodes a component of the cohesin complex that accumulates during meiotic S phase, and which is essential for chromosome synapsis and segregation. This RA induction of <i>Rec8</i> occurs in parallel with the induction of <i>Stra8</i>, and independently of <i>Stra8</i> function, and it is conserved between the sexes. Further, RA induction of <i>Rec8</i>, like that of <i>Stra8</i>, requires the germ-cell-intrinsic competence factor <i>Dazl</i>. Our findings strengthen the importance of RA and <i>Dazl</i> in the meiotic transition, provide important details about the <i>Stra8</i> pathway, and open avenues to investigate early meiosis through analysis of <i>Rec8</i> induction and function.</p>