title: Myc and Max: molecular evolution of a family of proto-oncogene products and their dimerization partner.
abstract: The myc gene family encodes a group of transcription factors that regulate cell proliferation and differentiation. These genes are widely studied because of their importance as proto-oncogenes. Phylogenetic analyses are described here for 45 Myc protein sequences representing c-, N-, L-, S-, and B-myc genes. A gene duplication early in vertebrate evolution produced the c-myc lineage and another lineage that later gave rise to the N- and L-myc lineages by another gene duplication. Evolutionary divergence in the myc gene family corresponds closely to the known branching order of the major vertebrate groups. The patterns of sequence evolution are described for five separate highly conserved regions, and these analyses show that differential rates of sequence divergence (= mosaic evolution) have occurred among conserved motifs. Further, the closely related dimerization partner protein Max exhibits significantly less sequence variability than Myc. It is suggested that the reduced variability in max stems from natural selection acting to preserve dimerization capability with products of myc and related genes.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D050976:Basic-Leucine Zipper Transcription Factors; D005075:Biological Evolution; D001717:Birds; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D005399:Fishes; D016259:Genes, myc; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D008322:Mammals; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D000090063:Proto-Oncogene Mas; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis / Q000737:chemistry; D011519:Proto-Oncogenes; D014157:Transcription Factors / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D014714:Vertebrates / Q000235:genetics*
chemical_list: D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; C000715470:MAS1 protein, human; C499330:MAX protein, human; C067850:Myc associated factor X; D000090063:Proto-Oncogene Mas; D016271:Proto-Oncogene Proteins c-myc; D014157:Transcription Factors