title: Effect of Phospholipase C-gamma1 Overexpression on the Protein Level of Waf1, PCNA, and Cyclin B1 Following Ultraviolet C Irradiation.
abstract: OBJECTIVE
  It has been demonstrated that PLC-gamma1 is overexpressed in many tumor cells, and that overexpression of Phospholipase C (PLC)-gamma1 is associated with tumor progression. In order to understand the effect of the PLC-gamma1 overexpression on the regulation of cell cycle regulators following DNA damage, we analyzed the expression level of PCNA, cyclin B1, and p21 Waf1 after ultraviolet C (UVC) irradiation in PLC-gamma1-transfected PC12 cells.
  
  
  METHODS
  PC12 and 3Y1 cells, transfected with empty vector or rat PLC-gamma1 cDNA, were used for this study. Following UVC irradiation, cell cycle progression was analyzed by flow cytometry and protein expression was detected by Western blotting.
  
  
  RESULTS
  Waf1 protein was markedly down-regulated, whereas PCNA and cyclin B1 was up-regulated in PLC-gamma1 overexpressed-cells as compared to the vector transfected-cells. When the cells were irradiated with UVC, PCNA was slightly increased within 3-hours of the UV irradiation and then was markedly decreased in Vector/ PC12 cells, while it remained high until 37 hour after UVC in PLC-gamma1/PC12 cells. In contrast, cyclin B1 was gradually decreased following UVC irradiation in both cells.
  
  
  CONCLUSIONS
  The overexpression of PLC-gamma1 affects the expression level of PCNA after UVC irradiation. We proposed that the overexpression of PLC-gamma1 may contribute to the UV-induced genomic instability by up-regulating the expression of PCNA.
authors.forename: S Y
authors.initials: SY
authors.lastname: Shin
authors.forename: Y H
authors.initials: YH
authors.lastname: Lee
authors.forename: S H
authors.initials: SH
authors.lastname: Baek
authors.forename: S Y
authors.initials: SY
authors.lastname: Kim
authors.forename: J R
authors.initials: JR
authors.lastname: Kim
authors.forename: J H
authors.initials: JH
authors.lastname: Kim
keywords: Cell cycle; Cyclin B1; Phospholipase C-gamma1; Proliferating cell nuclear antigen; Waf1