Hormonal regulation of transcription of rDNA. Purification and characterization of the hormone-regulated transcription factor IC.
Glucocorticoids reversibly inhibit transcription of ribosomal RNA genes in murine lymphosarcoma P1798 cells in culture. Inhibition of rDNA transcription is due to reduction in the amount or activity of an RNA polymerase I transcription factor called transcription factor IC (TFIC). TFIC has been purified over 100,000-fold. The highly purified preparation contains neither RNA polymerase I activity nor any of the conventional RNA polymerase I subunits. TFIC activity co-purifies with three polypeptides of approximately 55, 50, and 42 kDa molecular mass. These polypeptides are present in a stoichiometric ration of 1:1:1.
Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston 77550.
P B
PB
Mahajan
E A
EA
Thompson
D000818:Animals; D002460:Cell Line; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004275:DNA, Ribosomal / Q000187:drug effects / Q000235:genetics*; D003907:Dexamethasone / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology; D007700:Kinetics; D008228:Lymphoma, Non-Hodgkin; D046911:Macromolecular Substances; D051379:Mice; D008970:Molecular Weight; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012318:RNA Polymerase I / Q000302:isolation & purification / Q000378:metabolism; D015183:Restriction Mapping; D013816:Thermodynamics; D014157:Transcription Factors / Q000302:isolation & purification* / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects*
D004275:DNA, Ribosomal; D005938:Glucocorticoids; D046911:Macromolecular Substances; D014157:Transcription Factors; D003907:Dexamethasone; D012318:RNA Polymerase I