Temporal expression of factors involved in chromatin remodeling and in gene regulation during early bovine in vitro embryo development.

Distinct epigenetic modification events regulate gene expression and chromatin structure during the period between the immature oocyte and the blastocyst. Throughout this developmental period, important methylation fluctuations occur on genomic DNA and histones. Finding single or combinations of factors, which are at work during this period is essential to understand the entire epigenetic process. With this in mind, we assessed the precise temporal expression profile, during preimplantation embryo development, of 15 key regulators involved in RNA, DNA or histone methylation, chromatin modification or silencing and transcription regulation. To achieve this, real-time RT-PCR was used to quantify the mRNA levels of ATF7IP, DMAP1, EHMT1, EHMT2, HELLS, JARID1A, JARID1B, JMJD1A, JMJD2A, LSD1, MeCP2, METTL3, PRMT2, PRMT5 and RCOR2, in the oocyte and throughout in vitro bovine embryo development. Our results demonstrate that all the 15 key regulators were present to different degrees in the developmental stages tested, and they can be divided into three different groups depending on their respective mRNA profile.