FIG. 2.

Northern hybridization of mRNA from BC-1, TPA-induced BC-1, and P3HR1 cell lines demonstrating the three classes of viral gene transcription. mRNA (500 ng per lane) was separated on 1% agarose-formaldehyde gel and transferred to nylon filters. The filters were hybridized with four DNA probes: (A) v-cyclin D, which represents class I transcription; (B) v-IRF, which represents class II transcription; (C) MCP, which represents class III transcription; and (D) β-actin to control for RNA integrity and equivalent loading.