Levels of mRNA for bone morphogenetic proteins, their receptors and SMADs in goat ovarian follicles grown in vivo and in vitro

Abstract

This study investigated the stability of housekeeping genes (glyceraldehyde-3-phosphate dehydrogenase, β-tubulin, β-actin, phosphoglycerate kinase (PGK), 18S rRNA, ubiquitin and ribosomal protein 19) and the levels of mRNA for bone morphogenetic protein-2 (BMP-2), -4 (BMP-4), -6 (BMP-6), -7 (BMP-7) and -15 (BMP-15), their receptors (BMPR-IA, -IB and -II) and Similar to Mothers Against Decapentaplegic (SMADs) (-1, -5 and -8) in goat follicles of 0.2, 0.5 and 1.0 mm, as well as in secondary follicles before and after culture for 18 days. β-tubulin and PGK were the most stable housekeeping genes and the levels of mRNA for BMP-2 in follicles of 0.2 mm were higher than in follicles of 0.5 and 1.0 mm. For BMP-4, -6 and -7, the highest levels of mRNA were found in follicles of 1.0 mm. The expression of BMPR-IB was higher in follicles of 0.2 mm, whereas the levels of BMPR-II were higher in follicles of 0.5 mm. The levels of mRNA for SMAD-5 were higher in follicles of 0.2 mm, whereas SMAD-8 had higher levels in 0.5-mm follicles. After culture, follicles showed increased levels of mRNA for BMP-2 and reduced mRNA for BMP-4, BMP-7, BMPR-IA and SMAD-5. In conclusion, β-tubulin and PGK are the most stable reference genes, and BMPs, their receptors and SMADs have variable levels of mRNA in the follicular size classes analysed.