Cloning of chicken growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) and characterization of their spatial and temporal expression

Abstract

The oocyte derived growth differentiation factor 9 (GDF9) andbone morphogenetic protein 15 (BMP15) have been demonstrated to beessential for ovarian follicle growth in mammals. However, little is knownabout their expression during ovarian development in birds. Therefore, inthe present study, we first cloned the full-length cDNAs for GDF9 andBMP15 from the chicken ovary. The cloned chicken GDF9 (454 aminoacids) and BMP15 (350 amino acids) share high homologies with theirmammalian counterparts, especially in their putative mature regions(GDF9: ~78%; BMP15: ~55%). Although the expression of GDF9 andBMP15 could be detected in all of the tissues examined by reverse tran-scription-polymerase chain reaction (RT-PCR), Northern blot analysisdemonstrated that GDF9 and BMP15 are predominantly expressed in theadult chicken ovary. To further elucidate their potential roles in ovariangrowth, we also investigated the ontogeny of expression of GDF9 andBMP15 in the developing ovaries of sexual immature chickens.Interestingly, the expression of GDF9 and BMP15 could be consistentlydetected in the developing ovaries of all stages examined (3-week, 6-week,10-week, 13-week and 16-week). These results, together with detection ofthe expression of GDF 9 and BMP15 receptors in chicken ovaries, clearlysuggest that both GDF9 and BMP15 play paracrine/autocrine roles incontrolling ovarian development in chicken.