FIG. 5.
Coimmunoprecipitation of host cell proteins with the V protein of SV5. 2fTGH and 2f/SV5-V cells were or were not treated with the proteasome inhibitor MG132 (10 μM) for 6 h, during which time they were also metabolically labeled with 35[S]methionine. Soluble antigen extracts were made, and the V protein was precipitated with MAb SV5-P-k. The precipitated polypeptides were separated on both 12 and 7% (inset) polyacrylamide gels. The lower of the two high-molecular-mass host cell bands that coprecipitated with V was identified by MALDI-TOF analysis as the 127-kDa subunit of UV DDB; the upper, 150-kDa band has yet to be identified (unpublished results).