Competitive recruitment of CBP and Rb-HDAC regulates UBF acetylation and ribosomal transcription.
RNA polymerase I (PolI) transcription is activated by the HMG box architectural factor UBF, which loops approximately 140 bp of DNA into the enhancesome, necessitating major chromatin remodeling. Here we show that the acetyltransferase CBP is recruited to and acetylates UBF both in vitro and in vivo. CBP activates PolI transcription in vivo through its acetyltransferase domain and acetylation of UBF facilitates transcription derepression and activation in vitro. CBP activation and Rb suppression of ribosomal transcription by recruitment to UBF are mutually exclusive, regulating in vivo PolI transcription through an acetylation-deacetylation "flip-flop." Thus, PolI transcription is regulated by protein acetylation, and the competitive recruitment of CBP and Rb.
Pelletier
G
G
Cancer Research Centre and Department of Medical Biology Laval University Hotel-Dieu de Quebec 11 cote du Palais G1R 2J6, Quebec, Canada.
Stefanovsky
V Y
VY
Faubladier
M
M
Hirschler-Laszkiewicz
I
I
Savard
J
J
Rothblum
L I
LI
Côté
J
J
Moss
T
T
D016475:3T3 Cells; D000107:Acetylation; D000818:Animals; D001667:Binding, Competitive; D050882:CREB-Binding Protein; D002843:Chromatin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D004789:Enzyme Activation; D006655:Histone Deacetylases / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008957:Models, Genetic; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D035463:Pol1 Transcription Initiation Complex Proteins; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012318:RNA Polymerase I / Q000378:metabolism; D051381:Rats; D016160:Retinoblastoma Protein / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012270:Ribosomes / Q000235:genetics*; D013379:Substrate Specificity; D015534:Trans-Activators / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D014158:Transcription, Genetic; D014982:Xenopus laevis / Q000235:genetics
D002843:Chromatin; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D035463:Pol1 Transcription Initiation Complex Proteins; D016160:Retinoblastoma Protein; D015534:Trans-Activators; D014157:Transcription Factors; C063844:transcription factor UBF; D050882:CREB-Binding Protein; C494364:Crebbp protein, mouse; C494365:Crebbp protein, rat; D012318:RNA Polymerase I; D006655:Histone Deacetylases