Abstract:Transcription factor nanog and oct-4 are the fundamental features of pluripotent Stem Cell, which are the key factors to keep their pluripotency and self-renew ability. We transplanted 10 fibroblast cells(BEF422) into bovine oocytes at GⅤ and MⅡstages respectively, and cultured the oocytes for 24 h in vitro, than we used the RT-PCR and immunofluorescence technique to check the expression and location of nanog and oct-4 in the injected oocytes. The results showed that nanog and oct-4 were all expressed in the injected oocytes and located on transplanted cells nuclear. However, they weren't detected in fibroblast cells and oocytes control group; This result demonstrated that GⅤ and MⅡ stage oocytes both can activate the transcription factor nanog and oct-4 expression to reprogram the fibroblast cells. This study will lay a foundation for further verifying the reprogramme mechanism and related material on donor cells and oocytes.