FIG 1.

RTA mediates the downregulation of HLA-DRα. (A) Quantitation of MHC-II transcripts by RT-PCR. The TRExBJAB-RTA cells were treated with 8 μg/ml of tetracycline for 48 h. RNA was isolated, and RT-PCR was performed. The relative levels of MHC-II were normalized to GAPDH. (B) BJAB cells were transfected with 0, 10, and 20 μg of pCDNA-RTA together with 10 μg of the indicated Myc-tagged MHC-II plasmid by electroporation. At 48 h posttransfection, the cells were lysed and subjected to WB analysis with RTA and Myc antibodies. (C) DG-75 and Ramos cells were cotransfected with 10 μg pCDNA-RTA and Myc–HLA-DRα by electroporation. At 48 h posttransfection, cells were lysed and subjected to WB analysis with RTA and Myc antibodies. (D) TRExBJAB-RTA cells were treated with 8 μg/ml of tetracycline. Forty-eight hours later, the cells were lysed and subjected to WB analysis using RTA and HLA-DRα antibodies. (E) TRExBCBL1-RTA cells were treated with 8 μg/ml of tetracycline, and 48 h later, the cells were lysed and subjected to WB analysis with RTA and HLA-DRα antibodies. Tet, tetracycline; RD, relative density.