Comparison of mitochondrial-related transcriptional levels of TFAM, NRF1 and MT-CO1 genes in single human oocytes at various stages of the oocyte maturation

The aim of the current study was to assess the mRNA levels of two mitochondria-related genes,including nuclear-encoded NRF1 [nuclear respiratory factor 1], mitochondrial transcription factor A [TFAM], and mitochondrial-encoded cytochrome c oxidase subunit 1 [MT-CO1] genes in various stages of the human oocyte maturation. Oocytes were obtained from nine infertile women with male factor undergoing in vitro fertilization [IVF]/intra-cytoplasmic sperm injection protocol. Mitochondrial-related mRNA levels were performed by single-cell TaqMan real-time PCR. the expression level of the target genes was low at the germinal vesicle stage [P>0.05]. Although the mRNA level of NRF1gene remained stable in metaphase I, the mRNA level of TFAM and MT-CO1 increased significantly [P<0.05].In metaphase II, the expression level of all genes increasedcompared to metaphase I [P<0.05]. The overexpression levels of NRF1, TFAM, and MT-CO1 genes are related to the oocyte maturation. Therefore, the current study could be used clinically to improve the successrate of IVF.