Study On The Effect Of PTEN On Homologous Recombination Rapair, Rad51 And Its Mechanism

Object To explore the potential role of PTEN on DNA double strand breaks (DSBs) homologous recombination repair,and the potential role of PTEN on Rad51.Methods The expression level of several genes which involved in DSBs repair by homologous recombination between PTEN+/+MEFs and PTEN-/-MEFs cells( PTEN deletion mouse embryo fibroblasts) were explored by semi-quantification RT-PCR. Immunofluorescence, to investigate the DNA DSBs in control PTEN+/+MEFs and PTEN-/-MEFs. Establishment of plxsp-HAGFP-Rad52 stably transfected PTEN+/+MEFs and PTEN-/-MEFs cells, to investigate the function of homologous recombination repair. The changes of cell radiosensitivity were observed by clone formation assay. The expression level of Rad51 between PTEN+/+MEFs and PTEN-/-MEFs cells was detected by RT-PCR after 2 Gy ~ 60 Coγ-ray irradiated. The expression level of Rad51 in PTEN-/-MEFs cells was detected by RT—PCR after LY—294002 treated.Results In PTEN-/-MEFs, the expression level of Rad51, Rad51ap1, Rad52 and Rad52b was decreased to some extent when compared to control PTEN+/+MEFs, the DNA DSBs was increased and the function of homologous recombination repair deficient had improved to a certain degree in stable transfection cells. Compared to control PTEN+/+MEFs, the radiosensitivity of PTEN-/-MEFs was decreased. And the expression level of Rad51 was increased after irradiation and LY-294002 treatment.Conclusion PTEN should play a potential role in repair of DNA DSBs and maintain the genome stability through regulates the expression level of such as Rad52 genes which involved in DSBs repair of homologous recombination repair. PTEN should play a potential role in Rad51 and regulate it through PI3K/AKT signal pathway.