title: Mouse and rat B-myc share amino acid sequence homology with the c-myc transcriptional activator domain and contain a B-myc specific carboxy terminal region.
abstract: B-myc is a member of the myc gene family. Previous studies indicate that the rat B-myc gene contains a single exon which shows 77% nucleotide homology to the second exon of the rat c-myc gene. Its open reading frame (ORF) encodes a polypeptide with a predicted molecular weight of 20 kD. We have isolated a new, larger rat B-myc genomic clone. Sequence analysis of this clone confirmed the presence of one single coding exon. Furthermore, a genomic mouse B-myc clone was identified and compared to the rat homolog. Nucleotide analysis of B-myc coding and non-coding sequences suggests that it may be a functional gene evolved by selective duplication of part of the second c-myc exon. Analysis of the rodent B-myc open reading frames revealed two in-frame amino acid duplications in mouse B-myc and a 96% conservation at the amino acid level. Both rat and mouse B-myc proteins contain an identical and unique stretch of 14 carboxy terminal amino acid residues not found in other myc proteins. In vitro translation of rat and mouse B-myc ORF's yielded proteins that migrated as 26 kD bands in SDS-PAGE and could be immunoprecipitated by a polyclonal panmyc antiserum. Immunostaining of human lymphoma cells transiently transfected with a B-myc expression vector showed that the protein was mainly localized to the nucleus.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002051:Burkitt Lymphoma / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005091:Exons; D016259:Genes, myc / Q000235:genetics; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D016366:Open Reading Frames; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D015534:Trans-Activators / Q000235:genetics*; D014162:Transfection
chemical_list: D018076:DNA, Complementary; D009687:Nuclear Proteins; D016271:Proto-Oncogene Proteins c-myc; D015534:Trans-Activators