Promoter activation by enhancer-dependent and -independent loading of activator and coactivator complexes.
Activation of the pDbeta1 promoter at the TCRbeta locus requires a functional distal enhancer, Ebeta. Here, we have analyzed the mechanism of promoter activation in thymocytes from mice containing or lacking Ebeta. We found that pDbeta1 shows a complex profile of transcription factor and chromatin remodeling complex occupancy even at Ebeta(-) alleles. The presence of Ebeta, however, results in a few specific changes in factor occupancy at the promoter. These differences correlate with localized alterations in histone modifications and in the recruitment of the basal transcriptional machinery. In addition, Ebeta is also bound by CBP and Pol II, suggesting a mechanism for delivery of a holoenzyme complex to the pDbeta1 promoter. These results illustrate a specialized, long-range function of an enhancer in the hierarchical events that regulate assembly of a cell type-specific promoter.
Spicuglia
Salvatore
S
Centre d'Immunologie de Marseille-Luminy, INSERM CNRS, Université de la Méditerranée, Case 906, 13288 Cedex 09, Marseille, France.
Kumar
Sanjeev
S
Yeh
Jung-Hua
JH
Vachez
Elodie
E
Chasson
Lionel
L
Gorbatch
Sophie
S
Cautres
Julie
J
Ferrier
Pierre
P
D016475:3T3 Cells; D000818:Animals; D001665:Binding Sites; D002843:Chromatin / Q000235:genetics / Q000276:immunology / Q000648:ultrastructure; D002874:Chromosome Mapping; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D019674:Genes, T-Cell Receptor beta / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009707:Nucleosomes / Q000235:genetics; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic
D002843:Chromatin; D004268:DNA-Binding Proteins; D009707:Nucleosomes