Document Detail

Sequence selectivity of c-Myb in vivo. Resolution of a DNA target specificity paradox.
MedLine Citation:
PMID:  10419522     Owner:  NLM     Status:  MEDLINE    
We have investigated the basis for the striking difference between the broad DNA sequence selectivity of the c-Myb transcription factor minimal DNA-binding domain R(2)R(3) in vitro and the more restricted preference of a R(2)R(3)VP16 protein for Myb-specific recognition elements (MREs) in a Saccharomyces cerevisiae transactivation system. We show that sequence discrimination in yeast is highly dependent on the expression level of Myb effector protein. Full-length c-Myb and a C-terminally truncated protein (residues 1-360) were also included in the study. All of the tested Myb proteins displayed very similar DNA binding properties in electrophoretic mobility shift assays. Only minor differences between full-length c-Myb and truncated c-Myb(1-360) were observed. In transactivation studies in CV-1 cells, the MRE selectivity was highest at low expression levels of Myb effector proteins. However, the discrimination between MRE variants was rapidly lost with high input levels of effector plasmid. In c-Myb-expressing K-562 cells, the high degree of MRE selectivity was retained, thereby confirming the relevance of the results obtained in the yeast system. These data suggest that the MRE selectivity of c-Myb is an intrinsic property of only the R(2)R(3) domain itself and that the transactivation response of a specific MRE in vivo may be highly dependent on the expression level of the Myb protein in the cell.
K B Andersson; T Berge; V Matre; O S Gabrielsen
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  274     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1999 Jul 
Date Detail:
Created Date:  1999-08-19     Completed Date:  1999-08-19     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  21986-94     Citation Subset:  IM    
Department of Biochemistry, University of Oslo, N-0316 Oslo 3, Norway.
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MeSH Terms
Base Sequence
Binding Sites
COS Cells
Cell Line
DNA-Binding Proteins / metabolism
Genes, Reporter
K562 Cells
Luciferases / genetics
Molecular Sequence Data
Oligodeoxyribonucleotides / chemistry,  metabolism
Promoter Regions, Genetic*
Proto-Oncogene Proteins / genetics,  metabolism*
Proto-Oncogene Proteins c-myb
Recombinant Fusion Proteins / biosynthesis
Saccharomyces cerevisiae / genetics
Substrate Specificity
Trans-Activators / genetics,  metabolism*
Transcriptional Activation
Reg. No./Substance:
0/DNA-Binding Proteins; 0/Oligodeoxyribonucleotides; 0/Proto-Oncogene Proteins; 0/Proto-Oncogene Proteins c-myb; 0/Recombinant Fusion Proteins; 0/Trans-Activators; EC 1.13.12.-/Luciferases

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