FIG. 5.

Amino acids 1 to 548 of CIITA are required for the strongest interaction between CIITA and BRG-1. (A) C-terminal deletions of CIITA were generated by deletion of cDNA sequences (see Materials and Methods). Acidic, region rich in aspartic and glutamic acid residues (amino acids 26 to 140); P/S/T, region rich in proline/serine/threonine residues (amino acids160 to 319); LRR, leucine-rich region (amino acids 985 to 1086). (B) Western analysis with anti-HA antiserum of coimmunoprecipitation of CIITA with anti-BRG-1 antiserum (lanes 1 to 6) or of cellular lysates (lanes 7 to 12). pBJ5-BRG-1 was cotransfected with a plasmid expressing the indicated form of CIITA into COS-1 cells, followed by immunoprecipitation (IP) and Western blot (WB) analysis. CIITA(K141L) and CIITA(K144L) are full-length CIITA proteins that have point mutations that change the indicated lysine residues to leucine. N.S., nonspecific band detected in COS-1 cell extracts by anti-HA antiserum.