Expression of histone modifying proteins and chromatin remodelling factors in swine oocytes and developing embryos.

摘要

Currently, the quality of oocytes matured in vitro is still not satisfactory. In fact, only 5-10% of oocytes were evaluated to be intrinsically capable to produce in vitro embryos with full developmental competence. Recent studies have highlighted the importance of epigenetics, a mechanism controlling activation and repression of gene expression, in embryonic development. Indeed, several proteins involved in histone modifications including histone deacetylase 1 (HDAC-1), lysine specific demethylase 1 (LSD-1), and brahma related gene 1 (BRG-1) were shown vital to early development. We described the presence of these proteins during porcine oocyte maturation and embryo development and investigated whether these proteins were also involved in the regulation of developmental competence. We detected the three proteins in all stages of development, but nuclear localization was not always confirmed. We noticed that these three proteins followed the same general trend before activation but while the fluorescence signal of HDAC-1 increased after activation those of LSD-1 and BRG-1 decreased. Moreover, oocytes and embryos of lower developmental competence were observed to have differences in the fluorescence signal of HDAC-1, LSD-1, and BRG-1. The occurrence of targeted LSD-1 histone modifications, histone 3 lysine 4 mono- (H3K4me1) and di- (H3K4me2) methylation, were also found to be different in embryos of different developmental competence. This study suggests that HDAC-1, LSD-1 and BRG-1 are developmentally regulated during early development of swine embryos and are potentially involved in the acquisition of the embryonic developmental competence.