UHRF2Induces Cell Cycle Arrest At G1Phase By Stabilizing P53

ObjectiveUHRF2（ubiquitin-like with PHD and ring finger domains2）is amulti-domain nuclear protein that plays an important role in the regulationof cell cycle and in epigenetic modifications. UHRF2has been shown to bea novel E3ubiquitin ligase mediating the ubiquitination of tumorsuppressor p53in vivo and in vitro. In addition, overexpression of UHRF2induces cell arrest at G1phase. However, the linking between UHRF2andp53, and its role in the regulation of cell cycle are not fully understood.Herein, We aims to study the molecular mechanisms of UHRF2induce cellcycle arrest at G1phase and to explore the role of UHRF2in the regulationof p53expression as well as related biological effects.MethodsConventional cell culture method was used to maintaining HEK293cells. Cell transfection was performed with transfection reagent accordingto the manual.48h later, the cells were collected for subsequent research.The expression level of proteins was determined by Western Blot. Thetranscription level of genes was detected by RT-PCR. The cell cycle distribution was analyzed by flow cytometry.ResultResult shows that UHRF2plays a new role in the regulation of p53expression. Overexpression of UHRF2increased p53as well as p21expression in UHRF2-transfected cells, but transfection of ΔRING-UHRF2could not do so. Furthermore, down-regulation of UHRF2in HEK293cellscaused marked decrease of p53protein levels. In sum, the Western Blottingshows that UHRF2may stabilize p53protein by ubiquitination.Furthermore, the combination of transfection with flow cytometry analysesrevealed that overexpression of UHRF2increased G1population in HEK293cells, however knock-down of p53by RNA interference (RNAi) abrogatedUHRF2overexpression-induced G1arrest, indicating that UHRF2inducedG1arrest is attributed to increased p53and p53-dependent p21expression.ConclusionTogether, these results suggest that UHRF2play an important role incell proliferation and cell cycle regulation. There may exist a link betweenUHRF2and p53ubiquitination. Overexpression of UHRF2may induce G1arrest through upregulating p53-dependent p21expression, which ispresumably involved in the regulation of cell cycle and DNA damageresponse (DDR). The mechanism by that UHRF2stabilizes p53and its rolein DDR need to be done in the future.