Fig 1: SLX4 interacts with both MutSa and MutSß through a conserved N-terminal region. (A) HeLa FITo cells were transfected with FLAG-HA-SLX4 (FHA-SLX4) vector before FLAG immunoprecipitation (IP) and western blotting, which shows that MSH2 co-immunoprecipitates with overexpressed SLX4. (B) IP of endogenous SLX4. Co-immunoprecipitation (coIP) of MSH2 with endogenous SLX4 is barely detectable compared to experiments using overexpressed FHA-SLX4 as in A. The asterisk indicates an aspecific band recognized by the anti-SLX4 antibody (C) Left panel: IP of endogenous SLX4 from a nuclear soluble fraction or a chromatin-solubilized fraction in which the coIP of MSH2, MSH3 and MSH6 is readily detected. Right panel: control of the fractionation by western blot against CHK1, mainly nuclear soluble, and SMC3 enriched in chromatin. (D) Scheme of SLX4 illustrating the location and conservation of a short domain representing the putative MSH2 binding domain (MSH2bd) deleted in SLX4?MSH2bd. Alignments were performed with ProViz (81). (E) HeLa FITo cells were transfected with FHA-SLX4 WT, FHA-SLX4?MSH2bd or FHA-SLX4FLW*, which is deficient for XPF binding, before FLAG IP and western blotting with the indicated antibodies.