Gene Expression in the Supporting Cells at the Onset of Meiosis in Rabbit Gonads

Subsequent to somatic gonadal sexual differentiation, germ cells enter meiosis or mitotic arrest in the ovary or testis, respectively. Among mice, these processes occur almost synchronically in fetal gonads and depend, among other factors, on the levels of retinoic acid (RA). In contrast to those in mice, rabbit germ cells enter meiosis or mitotic arrest after birth and coexist with proliferating germ cells. Here, we studied the somatic cell context in which germ cells enter meiosis or mitotic arrest in the rabbit. Using confocal immunofluorescence and real-time PCR, we studied the expression profiles of ALDH1A1 and ALDH1A2 and, comprising 2 genes required for RA synthesis, 2 meiosis markers STRA8 and SYCP3 as well as 2 genes involved in meiosis inhibition, CYP26B1 and NANOS2. We found that although both meiosis and mitotic arrest initiate after birth, these 2 processes are regulated in a way similar to the human fetal gonad. Current results reinforce the value of the neonatal rabbit gonad as an alternative experimental model for analyzing the direct effect of environmental factors during critical stages of germ cell establishment.