Porcine DAZL messenger RNA: Its expression and regulation during oocyte maturation

Deleted in Azoospermia-Like (DAZL) is known to play an important role during both spermatogenesis and oogenesis, as mutations in this gene may result in male and female sterility. In order to study the expression of DAZL in the pig, we cloned the full-length coding sequence and determined its mRNA and protein expression profile in the ovary and in oocytes undergoing in vitro maturation (IVM). Immunohistochemisty revealed that DAZL protein localizes to oocytes of both preantral and antral follicles. The expression in the oocytes was also confirmed by Western blot. Immunocytochemistry and real time RT-PCR showed that the DAZL transcript and protein accumulate during oocyte maturation. In addition, glial cell line-derived neurotrophic factor (GDNF), epidermal growth factor (EGF), and follicle-stimulating hormone (FSH) significantly stimulate DAZL expression in oocytes derived from antral follicles during IVM. Our results suggest that the porcine DAZL coding sequence is highly homologous to those reported for the human and mouse cDNAs, and that DAZL expression increases during oocyte maturation.