title: Transcription in yeast: a factor that stimulates yeast RNA polymerases.
abstract: Yeast cells contain an RNA polymerase factor, pi, which is a heat-stable protein with an apparent molecular weight of 12,000. This factor stimulates transcription of calf-thymus, salmon-sperm, yeast-nuclear, and T4-phage DNA. It stimulates transcription by each of the four yeast-nuclear RNA polymerases, by rat-liver RNA polymerases I and II, and by Escherichia coli RNA polymerase. pi-Factor can cause each of the eukaryotic RNA polymerases to become insensitive to rifamycin AF-013, but does not stop inhibition of E. coli RNA polymerase by rifamycin AF-013. Stimulation of transcription by pi-factor is general, and does not apply only to a limited class of genes. Apparently, pi-factor stimulates transcription by increasing the proportion of RNA polymerase binding events that leads to the initiation of RNA chains.
mesh_terms: D000645:Ammonium Sulfate; D000818:Animals; D002417:Cattle; D002458:Cell Fractionation; D002467:Cell Nucleus / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D003090:Coliphages / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology; D005656:Fungal Proteins / Q000494:pharmacology*; D008099:Liver / Q000201:enzymology; D008297:Male; D009691:Nucleic Acid Denaturation; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D012294:Rifamycins / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D012474:Salmon; D013094:Spermatozoa / Q000378:metabolism; D013268:Stimulation, Chemical; D013698:Templates, Genetic; D013950:Thymus Gland / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: D004279:DNA, Viral; D005656:Fungal Proteins; D012294:Rifamycins; D004247:DNA; D012321:DNA-Directed RNA Polymerases; D000645:Ammonium Sulfate