Expression of the MUC1 gene in SKI-DLCL-1.

(A) Expression of mRNA was evaluated by Northern blot hybridization. One microgram of poly-A+ RNA was electrophoresed on a 1% formaldehyde agarose gel. The blot was hybridized successively with an MUC1 probe and a β-actin probe. Length of exposure on film is 1 hour for both probes. Lanes 1 to 6 represent different cell lines: lane 1, SKI-DLCL-1; lane 2, OCI-Ly8; lane 3, Daudi; lane 4, FL-318; lane 5, Raji; lane 6, Molt-4. (B) Protein expression was evaluated by Western blot hybridization using the MUC1-specific monoclonal antibodies HMFG1 (glycosylation sensitive) and HMFG2 (specific for the repeat motif). Lane 1, Raji; lane 2, MCF-7; lane 3, primary ascites; lane 4, SKI-DLCL-1. (C) Immunofluorescence was used to assess cell-surface expression. Staining of SKI-DLCL-1 cells and MCF-7 cells with HMFG2 antibody demonstrated a strong expression of MUC1. OCI-LY8 cells were used as a negative control in this experiment.