Fig. 1. CIITA mRNA and protein expression in melanoma cell lines. Total RNA was extracted from melanoma cells. Promoter III-derived CIITA mRNA (A), promoter IV-derived CIITA mRNA (B), and actin mRNA (C) were analyzed by RT-PCR. D, RNA was isolated from the normal human melanocytes, NHM 4528 cells, treated with 400 units/ml IFN- for 48 h or left untreated. The RNA was analyzed for promoter III- or promoter IV-derived CIITA mRNA and for actin mRNA. E, nuclear extracts were isolated and subjected to 410% gradient SDS-PAGE and transferred to polyvinylidene difluoride membranes. The blot was then probed with anti-CIITA sera and developed by ECL (Amersham). IFN- treatments for 24 h are as indicated. F, cotransfection of a CIITA expression vector and an HLA-DRA promoter-luciferase construct. Cell lines are as indicated.