Figure 4.

Expression of BRCA1 protein by immunoprecipitation and Western blotting using the mAb MS-110. a, Lanes 1 and 2 show L56Br-X1 and the wild-type control (breast cancer cell line HBL-100), respectively, where BR1S060.2 (10 μg) was used to immunoprecipitate BRCA1 proteins from the lysates. B, Lanes 1 and 2 show L56Br-X1 and the wild-type control (breast cancer cell line HBL-100), respectively, where MS110 (6 μg) was used to immunoprecipitate BRCA1 proteins from the lysates. Gray arrows indicate the position of BRCA1 220 kd. Lanes 3 and 4 show L56Br-X1 and the control HBL-100 cell line at the position of 63 kd (black arrow), where the truncated BRCA1 protein of 563 amino acids resulting from the mutation Q563X is expected to migrate.