DNA binding activity and transcriptional activator function of the human B-myb protein compared with c-MYB.
Three members of the myb gene family have been identified in human cDNA libraries c-myb, A-myb, and B-myb. We compared the DNA binding properties of the B-myb and c-myb proteins (B-MYB and c-MYB) using bacterially synthesized B-MYB and c-MYB in DNase I footprinting. B-MYB bound to most of the c-MYB binding sites examined, including the c-MYB binding site, MBS-I, in the simian virus (SV) 40 enhancer, in which the most frequent sequence was CCTAACTG. The MBS-I site was an enhancer element dependent on B-MYB and c-MYB in a co-transfection assay that used the B-myb or c-myb expression plasmid. Some sites in the SV40 genome, including the MBS-BI site, had high affinity with B-MYB but little or no affinity with c-MYB, in which the most frequent sequence was AGAAANPyrG. The MBS-BI site was an enhancer element dependent on B-MYB and a very weakly dependent on c-MYB. Our results showed that B-MYB is a transcriptional activator, like c-MYB, and that although B-MYB and c-MYB have similar sequence specificity for DNA binding some sequences were recognized by B-MYB preferentially.
Mizuguchi
G
G
Tsukuba Life Science Center, Institute of Physical and Chemical Research, Ibaraki, Japan.
Nakagoshi
H
H
Nagase
T
T
Nomura
N
N
Date
T
T
Ueno
Y
Y
Ishii
S
S
D001483:Base Sequence; D001665:Binding Sites; D018797:Cell Cycle Proteins; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D003850:Deoxyribonuclease I; D004742:Enhancer Elements, Genetic / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005814:Genes, Viral; D005914:Globins / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D010957:Plasmids; D011401:Promoter Regions, Genetic / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D020598:Proto-Oncogene Proteins c-myb; D011994:Recombinant Proteins / Q000378:metabolism; D013539:Simian virus 40 / Q000235:genetics; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C064352:MYBL2 protein, human; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D011994:Recombinant Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D005914:Globins; D004247:DNA; D003850:Deoxyribonuclease I