Bright/ARID3A contributes to chromatin accessibility of the immunoglobulin heavy chain enhancer.

Full Abstract

Bright/ARID3A is a nuclear matrix-associated transcription factor that stimulates immunoglobulin heavy chain (IgH) expression and Cyclin E1/E2F-dependent cell cycle progression. Bright positively activates IgH transcriptional initiation by binding to ATC-rich P sites within nuclear matrix attachment regions (MARs) flanking the IgH intronic enhancer (Emu). Over-expression of Bright in cultured B cells was shown to correlate with DNase hypersensitivity of Emu. We report here further efforts to analyze Bright-mediated Emu enhancer activation within the physiological constraints of chromatin. A system was established in which VH promoter-driven in vitro transcription on chromatin- reconstituted templates was responsive to Emu. Bright assisted in blocking the general repression caused by nucleosome assembly but was incapable of stimulating transcription from prebound nucleosome arrays. In vitro transcriptional derepression by Bright was enhanced on templates in which Emu is flanked by MARs and was inhibited by competition with high affinity Bright binding (P2) sites. DNase hypersensitivity of chromatin-reconstituted Emu was increased when prepackaged with B cell nuclear extract supplemented with Bright. These results identify Bright as a contributor to accessibility of the IgH enhancer.

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Author information

Author/s: Lin, Danjuan (D); Ippolito, Gregory C (GC); Zong, Rui-Ting (RT); Bryant, James (J); Koslovsky, Janet (J); Tucker, Philip (P);

Affiliation: Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA. djlin@mail.utexas.edu

Grants: 1F32CA110624-01A1 (Agency:United States NCI) ; CA31534 (Agency:United States NCI)

Journal and publication information

Publication Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't

Journal: Molecular cancer (Mol Cancer), published in England. (Language: eng)

Reference: 2007-; vol 6 (issue ) : pp 23

Dates: Created 2007/04/16; Completed 2007/05/02; Revised 2007/12/03;

PMID: 17386101, status: MEDLINE (last retrieval date: 11/6/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Cell Line
Chromatin - genetics; metabolism
DNA-Binding Proteins - metabolism
Deoxyribonucleases - metabolism
Enhancer Elements (Genetics) - genetics
Humans

Immunoglobulin Heavy Chains - genetics
Oncogenes
Promoter Regions (Genetics) - genetics
Protein Binding
Trans-Activators - metabolism
Transcription, Genetic - genetics

Associated Chemicals: ARID3A protein, human (0) ; Chromatin (0) ; DNA-Binding Proteins (0) ; Immunoglobulin Heavy Chains (0) ; Trans-Activators (0) ; Deoxyribonucleases (EC 3.1.-)

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