OCT-4 GENE EXPRESSION PATTERN IN DIFFERENT GRADES OF BUFFALO (Bubalus bubalis) OOCYTES

The developmental competence of oocytes may be a function of the presence/abundance of specific transcripts in their mRNA pools, since the earlier stages of embryogenesis in mammals and other animals are regulated by maternally-inherited RNAs and proteins stored within the oocyte. This study was undertaken to test the hypothesis that naked oocytes which are proved to be of low developmental potential are devoid of Oct-4 gene expression. It was observed that culture grade ('A' and 'B' grade) oocytes showed strong Oct-4 expression whereas naked oocytes showed faint or no detectable signal. A fragment of 196 bp product was detected in Oct-4 positive oocytes. It was observed that culture grade oocytes showed strong Oct-4 expression with a dense band whereas naked oocytes showed a faint band. Out of twenty trials, a thick fragment of 196 bp product (EU661360) was detected in all trials of culture grade oocytes whereas in naked oocytes only a faint band was observed in twelve trials (60%) and no band at all in the remaining eight (40%) trials. Based on the results, it was concluded that Oct-4 may be one of those specific genes whose expression is dependent on oocyte quality, suggesting that the lower developmental potential of naked oocytes might be due to the absence of Oct-4 transcripts.