Padrão de metilação dos genes IGF2 e XIST em ovócitos oriundos de folículos pré-antrais de vacas Nelore (Bos taurus indicus)

Abstract

In order to increase productivity looking for maximum use of genetic material available, various reproductive biotechnologies have been developed and used. Despite the fact that the oocytes obtained from preantral follicles have not been able to produce embryo yet, they are a very important source of gametes to be used in vitro of embryos. It is necessary to understand the epigenetics reprogramming that occurs in these oocytes when there is a future possibility of use of these oocytes obtained from preantral follicles for embryo production. This study focus on evaluating the methylation pattern in a DMR of the last exon of IGF2 gene in oocytes of 65-90 μm, and of exon 1 of the XIST gene in oocytes ≤ 20 μm, and 65-90 μm obtained from preantral follicles. For the IGF2, the oocytes from secondary follicles ends of 65-90 μm presented 31,09 ± 31,01% of methylation, and for the XIST, the oocytes of primordial follicles ≤ 20 μm, and the oocytes of secondary follicles ends of 65-90 μm presented 15,17 ± 32,82% and 4,6 ± 3,46% respectively. The IGF2 was hipomethylated and being analysed by the literature data, it is observed that this region of the gene suffer a reprogramming process during oogenesis. The XIST presented a demethylation process throughout the development of the oocyte tending to remain until fertilization. In conclusion, these two genomic regions suffers an epigenetic reprogramming process during gametegenesis.