E2F1 and infection: Indeed, the decrease of E2F1 was dependent on Salmonella internalization, since a Salmonella mutant strain defective in invasion (ΔSPI-1 strain) was not able to elicit this phenotype, whereas infection with a strain able to invade but defective in intracellular replication (ΔSPI-2 strain) led to E2F1 downregulation (Supplementary Fig. 1f and ref. 27).