Lanes 1, 2, 5 & 6 : Anti-DNA polymerase eta antibody ( ab17725 ) at 1/400 dilution Lanes 3 - 4 : Anti-DNA polymerase eta antibody ( ab17725 ) at 1/2000 dilution Lane 1 : XP30RO cell lysate (cells lacking endogenous DNA polymerase eta) Lane 2 : MRC5 cell lysate Lane 3 : XP30RO cell lysate (cells lacking endogenous DNA polymerase eta) Lane 4 : MRC5 cell lysate Lane 5 : XP30RO cell lysate (cells lacking endogenous DNA polymerase eta) Lane 6 : MRC5 cell lysate Secondary Goat anti-rabbit HRP at 1/5000 dilution developed using the ECL technique Performed under reducing conditions. Exposure time : 20 minutes