An E4 34k/ligase IV complex in extracts from H5dl1016-infected cells. HeLa cells were Mock-, Ad5- or H5dl1016-infected and lysed in NP40 lysis buffer 20 h post-infection. 200 μg of extract was subject to IP with anti-E4 34k antibodies. E4 34k-containing complexes were resolved on SDS-PAGE, Western transferred and probed for Ligase IV, XRCC4 and E4 34k. I, 15% of input lysate; IP, immunoprecipitation using anti-E4 34k antibodies; C, control IP.