max encodes a sequence-specific DNA-binding protein and is not regulated by serum growth factors.
Max and c-Myc proteins, produced in bacteria, were studied for DNA-binding activity using the electrophoretic band-shift assay (EMSA). Both Max homodimers and c-Myc-Max heterodimers selected the same sequence CA(C/T)GTG from an initial pool of 10(6) DNA molecules. From the pool of sequence-specific binding sites, the palindromic site (CACGTG) was preferentially selected over the CATGTG site using two different degenerate oligonucleotide probes. max expression is identical in myc-induced tumor cell lines relative to other cells. Furthermore, max expression is constant in both confluent and serum-stimulated A31 fibroblasts, in contrast to c-myc expression, which is barely detectable in confluent fibroblasts and induced 20-fold by serum growth factors. Based on recognition of the same DNA sequence by Max and c-Myc-Max complexes and differential expression of the two genes, we propose that Max homodimers and c-Myc-Max heterodimers may bind to a common set of cellular target genes.
Berberich
S
S
Department of Molecular Biology, Princeton University, New Jersey 08544-1014.
Hyde-DeRuyscher
N
N
Espenshade
P
P
Cole
M
M
D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000502:physiology*; D005786:Gene Expression Regulation; D006133:Growth Substances / Q000494:pharmacology; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D011485:Protein Binding; D016271:Proto-Oncogene Proteins c-myc / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D013329:Structure-Activity Relationship; D014157:Transcription Factors
D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D006133:Growth Substances; D046911:Macromolecular Substances; C067850:Myc associated factor X; D009838:Oligodeoxyribonucleotides; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D014157:Transcription Factors