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Mga, a dual-specificity transcription factor that interacts with Max and contains a T-domain DNA-binding motif.

Hurlin, P J and Steingrìmsson, E and Copeland, N G and Jenkins, N A and Eisenman, R N (1999) Mga, a dual-specificity transcription factor that interacts with Max and contains a T-domain DNA-binding motif. The EMBO journal, 18 (24). pp. 7019-7028. ISSN 0261-4189

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The basic-helix-loop-helix-leucine zipper (bHLHZip) proteins Myc, Mad and Mnt are part of a transcription activation/repression system involved in the regulation of cell proliferation. The function of these proteins as transcription factors is mediated by heterodimerization with the small bHLHZip protein Max, which is required for their specific DNA binding to E-box sequences. We have identified a novel Max-interacting protein, Mga, which contains a Myc-like bHLHZip motif, but otherwise shows no relationship with Myc or other Max-interacting proteins. Like Myc, Mad and Mnt proteins, Mga requires heterodimerization with Max for binding to the preferred Myc-Max-binding site CACGTG. In addition to the bHLHZip domain, Mga contains a second DNA-binding domain: the T-box or T-domain. The T-domain is a highly conserved DNA-binding motif originally defined in Brachyury and characteristic of the Tbx family of transcription factors. Mga binds the preferred Brachyury-binding sequence and represses transcription of reporter genes containing promoter-proximal Brachyury-binding sites. Surprisingly, Mga is converted to a transcription activator of both Myc-Max and Brachyury site-containing reporters in a Max-dependent manner. Our results suggest that Mga functions as a dual-specificity transcription factor that regulates the expression of both Max-network and T-box family target genes.

Item Type: Article or Abstract
Additional Information: This article is freely available in PubMed Central and at the journal's website.
DOI: 10.1093/emboj/18.24.7019
PubMed ID: 10601024
PMCID: PMC1171765
Grant Numbers: CA20525
Keywords or MeSH Headings: Amino Acid Sequence; Animals; Base Sequence; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Basic-Leucine Zipper Transcription Factors; Binding Sites; Cloning, Molecular; DNA-Binding Proteins/chemistry/metabolism; Dimerization; Embryonic and Fetal Development; Fetal Proteins/genetics/metabolism; Gene Expression Regulation, Developmental; Helix-Loop-Helix Motifs; Leucine Zippers; Mice; Molecular Sequence Data; Proto-Oncogene Proteins c-myc/chemistry/metabolism; Recombinant Proteins/chemistry/metabolism; Sequence Alignment; Sequence Homology, Amino Acid; T-Box Domain Proteins/genetics/metabolism; Transcription Factors/chemistry/genetics/metabolism;
Subjects: Molecules > Proteins > Transcription factors
Molecules > Genes > Oncogenes
Depositing User: Library Staff
Date Deposited: 25 Nov 2008 19:21
Last Modified: 07 May 2010 20:50

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