Figure 3.
Nuclear run-on analysis after treatment of MCF-7 cells with tRA. Nuclei were prepared from cells incubated with 1 μM tRA for time periods as indicated. Transcription of the isolated nuclei was analyzed by hybridization of 32P-labeled RNA to 22 μg of human NIS and human β-actin cDNAs immobilized on nylon membranes. (a) Representative of three experiments performed with similar results. (b) Densitometric analysis of three independent run-on assays. Signals of NIS were quantified and normalized to those of β-actin. Data at 0 h are arbitrarily assigned a value of 1, and intensities of NIS are expressed as a fold increase over that basal value. Values are means ± SD (n = 3). P < 0.03, at 12 h when compared with the group at 0 h.