OCA-B is a functional analog of VP16 but targets a separate surface of the Oct-1 POU domain

Babb, R., Cleary, M. A., Herr, W. (December 1997) OCA-B is a functional analog of VP16 but targets a separate surface of the Oct-1 POU domain. Molecular and Cellular Biology, 17 (12). pp. 7295-305. ISSN 0270-7306 (Print)

Abstract

OCA-B is a B-cell-specific coregulator of the broadly expressed POU domain transcription factor Oct-1. OCA-B associates with the Oct-1 POU domain, a bipartite DNA-binding structure containing a POU-specific (POU[S]) domain joined by a flexible linker to a POU homeodomain (POU[H]). Here, we show that OCA-B alters the activity of Oct-1 in two ways. It provides a transcriptional activation domain which, unlike Oct-1, activates an mRNA-type promoter effectively, and it stabilizes Oct-1 on the Oct-1-responsive octamer sequence ATGCAAAT. These properties of OCA-B parallel those displayed by the herpes simplex virus Oct-1 coregulator VP16. OCA-B, however, interacts with a different surface of the DNA-bound Oct-1 POU domain, interacting with both the POU(S) and POU(H) domains and the center of the ATGCAAAT octamer sequence. The OCA-B and VP16 interactions with the Oct-1 POU domain are sufficiently different to permit OCA-B and VP16 to bind the Oct-1 POU domain simultaneously. These results emphasize the structural versatility of the Oct-1 POU domain in its interaction with coregulators.

Item Type: Paper
Uncontrolled Keywords: Amino Acid Sequence B-Lymphocytes/metabolism Base Sequence Binding Sites/genetics DNA/genetics/metabolism DNA Primers/genetics DNA-Binding Proteins/chemistry/genetics/ metabolism Hela Cells Herpes Simplex Virus Protein Vmw65/genetics/ metabolism Host Cell Factor C1 Humans In Vitro Models, Molecular Molecular Sequence Data Mutagenesis, Site-Directed Octamer Transcription Factor-1 Polymerase Chain Reaction Promoter Regions (Genetics) Protein Conformation RNA, Messenger/genetics Research Support, U.S. Gov't, P.H.S. Trans-Activators/chemistry/genetics/ metabolism Transcription Factors/chemistry/genetics/ metabolism
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes > DNA polymerase
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > DNA binding protein
organism description > virus > herpes simplex virus
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > mutations > mutagenesis
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > transcription factor
CSHL Authors:
Communities: CSHL labs > Herr lab
Depositing User: Kathleen Darby
Date: December 1997
Date Deposited: 07 May 2014 17:34
Last Modified: 07 May 2014 17:34
Related URLs:
URI: https://repository.cshl.edu/id/eprint/30021

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