BRCA-1 Gene Expression and Comparative Proteomic Profile of Primordial Follicles from Young and Adult Buffalo (Bubalus bubalis) Ovaries.

In our previous study, we demonstrated that the repair efficiency of DNA double-strand breaks declines with increasing age in rat primordial follicles. In the present study, we extended our studies to buffalo (Bubalus bubalis) wherein we studied the expression of BRCA-1 related DNA repair genes in primordial follicles of young (12 months-22 months) and adult (72-96 months) buffaloes. The relative expression of selected genes, as determined by RT-PCR, revealed a significant (p < 0.05) decrease in mRNA levels of BRCA1, MRE11, RAD51, ATM, and H2AX in adult primordial follicles as compared to the young. Western blot analysis revealed a significant (p < 0.05) decrease in the expression of phosphorylated protein levels of BRCA1 and H2AX in adult buffalo primordial follicles. The protein expression profile of young and adult buffalo primordial follicles revealed differential expression of proteins involved in mitochondrial function, cell survival and cell metabolism. Similar to reports from aging rodent and human primordial follicles, our findings support the fact that impairment of DNA repair may be an universal mechanism involved in oocyte aging.