FIG. 5.

Specific BAF155 domains are required for increasing the BAF57 protein level and the interaction with BAF57 in vivo. (A) Schematic illustration of human BAF155 domain structure and the various deletion constructs used in this study. All mutants were fused to a nuclear localization signal (NLS) and Myc epitope at the C terminus. P/Q, proline- and glutamine-rich region; LZ, leucine zipper. (B) Whole-cell extracts from UL3/BAF57ΔHMG-1 cells transiently transfected with either an empty vector (lane a), wt BAF155 (lane b), or various deletion mutant expression vectors (lanes c to i) were analyzed by Western blotting with either BAF57 antibody (top panel) or Myc antibody (bottom panel). β-Actin was used as an internal loading control (middle panel). (C) Whole-cell extracts were prepared from UL3 cells transiently transfected with BAF57-FLAG and various BAF155 mutant expression vectors and immunoprecipitated with Myc antibody. The precipitated materials were analyzed by Western blotting with FLAG-horseradish peroxidase (FLAG-HRP) antibody (top panel). The same blot was stripped and reprobed with Myc-HRP antibody (middle panel) to demonstrate the IP efficiency. The bands corresponding to the expected BAF155 protein are marked with dots. About 5% of the total input lysates used for immunoprecipitation were directly analyzed by Western blotting with FLAG antibody (bottom panel).