Interaction of the v-and c-Myb proteins with regulatory sequences of the human c-myc gene.
Eight c-Myb-binding sites have been identified in the regulatory region of the human c-myc gene using gel retardation and DNAase I footprint assays with purified bacterially expressed full-length and carboxy-terminally truncated c-Myb proteins. These binding sites exhibit different affinities whereby strong binding correlates better with conservation of the palindromic sequences, AACXGTT or AACGTT, than the previously described consensus sequence. Flanking AT-rich sequences further increase the binding affinity. The c-Myb-binding sites are arranged in pairs consisting of one high- and one low-affinity binding site. Binding of the Myb proteins to these sites is non-cooperative. The v-Myb protein protects two nucleotides fewer than the c-Myb protein. Co-transfection of reporter CAT genes, containing upstream human c-myc sequences including exon 1, with c-Myb-expressing constructs resulted in positive transactivation, which was eightfold with full-length Myb and 14-fold with the truncated Myb. This result suggests that the Myb protein could participate in regulation of human c-myc gene expression.
Max-Planck-Institut fuer Molekulare Genetik, Abt. Schuster, Berlin, Germany.
A
A
Zobel
F
F
Kalkbrenner
S
S
Guehmann
M
M
Nawrath
G
G
Vorbrueggen
K
K
Moelling
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D004247:DNA / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000494:pharmacology; D005091:Exons; D005786:Gene Expression Regulation / Q000235:genetics*; D016259:Genes, myc / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D012150:Polymorphism, Restriction Fragment Length; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D020598:Proto-Oncogene Proteins c-myb; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D014162:Transfection
D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D016271:Proto-Oncogene Proteins c-myc; D004247:DNA; D015500:Chloramphenicol O-Acetyltransferase; D003850:Deoxyribonuclease I