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Pinar Tulay Vehit
Near East University, Cyprus
Posters & Accepted Abstracts: Transcriptomics
Introduction: The expression of parental genomes is required for completion of embryogenesis. Differential methylation of each parental genome has been observed in mouse and human preimplantation embryos. It is possible that differences in methylation affect the level of gene transcripts from each parental genome in early developing embryos. The aim of this study was to investigate if there is a parent specific pattern of BRCA1 expression in human embryos and to examine if this affects embryo development when the embryo carries a BRCA mutation. Materials and Methods: Differential parental expression of ACTB, SNRPN, H19 and BRCA1 was semi-quantitatively analysed by mini-sequencing in 95 human preimplantation embryos obtained from couples undergoing preimplantation genetic diagnosis (PGD). Results: BRCA1 was shown to be differentially expressed favouring the paternal transcript in early developing embryos. Methylation specific PCR showed a variable methylation profile of BRCA1 promoter region at different stages of embryonic development. Embryos carrying paternally inherited BRCA mutations were shown to develop more slowly compared to the embryos with maternally inherited BRCA mutations. Conclusions: The results of this study suggest that differential gene expression can influence the early development of preimplantation embryos. When the paternal BRCA1 transcript present in the embryo carries a mutation, the embryo may become more vulnerable to stress due to rapid demethylation of the paternal genome and the gradual demethylation of the maternal genome. Further extrapolation of this data suggests that the risk of transmitting a BRCA mutation may be modulated by the parental origin of the mutation.