MCM6 and infection: MCM complexes were depleted by infection with lentiviruses expressing short hairpin RNAs (shRNAs) targeting Mcm6 (shMcm6), with an shRNA against LacZ (β-Galactosidase) (shLacZ) serving as a control for infection and shRNA expression, as described previously13,39 (Supplementary Fig. 1b).