Transcriptional Regulation And Functional Analysis Of VDAC2

The litter size of domestic pigs is much higher than their closest wild relative through long-term domestication, the development and apoptosis of follicles are important factors to determine the litter size. Previous studies using the2DE-DIGE-MS technique have identified that VDAC2is one of the differentially expressed proteins in ovaries between domestic and wild pigs. In this study, we further identified its transcriptional regulation mechanisms and roles in autophagy.VDAC2(voltage-dependent anion channel protein2) is a member of VDAC family, which was widely distributed in all eukaryotic mitochondrial outer membrane. Its closure or open can control the mitochondrial membrane permeability changes, release of cytochrome C and apoptotic factors ultimately leading to apoptosis. A lot of evidences showed that VDAC2plays important roles in apoptosis and in sperm motility and fertilization capacity.To realize possible roles of VDAC2in ovary development, RT-PCR, Western blot and immunofluorescence experiments were used to observe its expression during ovary development. Immunofluorescence experiments showed VDAC2expressed firstly in the interstitial cell,and experssed high level in granular cell after dpp14.To study the transcriptional regulation of VDAC2,a2.8Kb promoter of mouse VDAC2was identified. Truncated mutations analysis of VDAC2promoter showed the core promoter, in which transcription factor binding sites and main transcription factors GATA1and B-Myb were further identified. Because of the CpG-rich island in VDAC2promoter, the VDAC2promoter methylation in oocytes and granulose cells in different stages after birth was then analysed, which showed non-methylated.To further realize biological functions of VDAC2, VDAC2knockout cell lines were used, which showed that VDAC2knockout promoted autophagy. During this process, VDAC2has direct interaction with the classical autophagy protein Beclinl.We believe that the VDAC2participates in autophagy by direct interaction with Beclinl and Bcl-xl. These results will provide key evidences supporting that VDAC2is potentially important during oogenesis in mamals.