title: p300-mediated tax transactivation from recombinant chromatin: histone tail deletion mimics coactivator function.
abstract: Efficient transcription of the human T-cell leukemia virus type 1 (HTLV-1) genome requires Tax, a virally encoded oncogenic transcription factor, in complex with the cellular transcription factor CREB and the coactivators p300/CBP. To examine Tax transactivation in vitro, we used a chromatin assembly system that included recombinant core histones. The addition of Tax, CREB, and p300 to the HTLV-1 promoter assembled into chromatin activated transcription several hundredfold. Chromatin templates selectively lacking amino-terminal histone tails demonstrated enhanced transcriptional activation by Tax and CREB, with significantly reduced dependence on p300 and acetyl coenzyme A (acetyl-CoA). Interestingly, Tax/CREB activation from the tailless chromatin templates retained a substantial requirement for acetyl-CoA, indicating a role for acetyl-CoA beyond histone acetylation. These data indicate that during Tax transcriptional activation, the amino-terminal histone tails are the major targets of p300 and that tail deletion and acetylation are functionally equivalent.
authors.affiliation: Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870, USA.
authors.forename: Sara A
authors.initials: SA
authors.lastname: Georges
authors.forename: W Lee
authors.initials: WL
authors.lastname: Kraus
authors.forename: Karolin
authors.initials: K
authors.lastname: Luger
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Nyborg
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Laybourn
mesh_terms: D000105:Acetyl Coenzyme A / Q000378:metabolism; D000107:Acetylation; D000818:Animals; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004331:Drosophila melanogaster; D016356:Gene Products, tax / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015368:Human T-lymphotropic virus 1 / Q000235:genetics*; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D015533:Transcriptional Activation; D014982:Xenopus laevis
chemical_list: D002843:Chromatin; D017362:Cyclic AMP Response Element-Binding Protein; D016356:Gene Products, tax; D006657:Histones; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D015534:Trans-Activators; D000105:Acetyl Coenzyme A; D004247:DNA