In contrast, infection of cells with viruses containing multialanine substitutions in either or both of the two acidic regions (133–138A and 6EP-12A mutants) showed that during infection, mutation of the 189–200 EP repeat, equivalent to auxiliary region 1 (16, 17), was primarily responsible for the decrease in transcriptional activation of E2, E3, and E4 by DM E1A (Fig. 4). Here, DHTKD1 is linked to infection.