Fig. 3. Recruitment of MSH3 to laser-irradiated site is mediated by PCNA. (A) Schematic representation of MSH3 and its deletion mutants and the results of recruitment experiments. Black and gray boxes indicate PCNA-binding motif and MSH2-binding domains, respectively. The site of mutation (F27A/F28A) is indicated with a cross. (B) GFP-MSH3 colocalizes with endogenous PCNA at sites of laser-irradiation. GFP-PCNA is recruited to the site of laser-irradiation in HCT116 cells (right panel). (C) Coexpression of GFP-MSH3 with mDR-PCNA wild-type (upper panels) or with mDR-PCNA mutant (D41A) (lower panels) in HeLa cells. (D) mDR-MSH2 was not recruited to the site of laser-irradiation by coexpression of the GFP-tagged mutant MSH3 (F27A/F28A) in HCT116 cells. Arrows indicate the sites of irradiation.