FIG. 2.
Nuclear run-on analysis. Newly synthesized and radiolabeled RNA from isolated nuclei were obtained as described in Materials and Methods. (A) RNA (4 × 106 cpm) from each of the indicated cell lines was allowed to hybridize with either FR-α or γ-actin cDNA containing plasmids (10 μg) which were previously immobilized by slot blot on nitrocellulose membranes. Immobilized plasmid vector was used as a negative control for each cell line. (B) As a positive control for FR-α gene transcription, HeLa cells were transfected with the FR-α cDNA under the control of the strong RSV promoter (RSV-FR-α) and subjected to nuclear run-on analysis as described above.