title: Translatable immunoglobulin germ-line transcript.
abstract: During B cell differentiation, the functional genes encoding immunoglobulin (Ig) heavy (H) and light (L) chains are generated by two rearrangement processes--VDJ rearrangement generates the exon encoding the Ig variable (V) regions, and the class switch reconstructs a rearranged IgH gene by exchanging the segment encoding the constant (C) region, which determines the Ig class. Both types of rearrangement are preceded by transcripts originating from a transcriptional start site 5' of the I exon, which is then spliced to the C exons. These germ-line transcripts, which are thought to be necessary for the initiation of both types of rearrangement, are said to be sterile. We demonstrate here that the mu germ-line transcript is translatable into a polypeptide chain, to which we assign the symbol psi. Thus, protein products of these transcripts might be part of or signal to the recombinases that catalyze Ig gene rearrangement.
authors.affiliation: Department of Microbiology and Immunology, University of California, San Francisco 94143-0670, USA.
authors.forename: J
authors.initials: J
authors.lastname: Bachl
authors.forename: C W
authors.initials: CW
authors.lastname: Turck
authors.forename: M
authors.initials: M
authors.lastname: Wabl
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004254:DNA Nucleotidyltransferases / Q000378:metabolism; D005091:Exons / Q000235:genetics; D015322:Gene Rearrangement, B-Lymphocyte; D017930:Genes, Reporter; D006801:Humans; D017578:Immunoglobulin Class Switching; D007127:Immunoglobulin Constant Regions / Q000235:genetics*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007075:Immunoglobulin M / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D014176:Protein Biosynthesis; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics*; D011993:Recombinant Fusion Proteins; D016415:Sequence Alignment; D017385:Sequence Homology; D014158:Transcription, Genetic; D014162:Transfection; D045567:VDJ Recombinases; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D007127:Immunoglobulin Constant Regions; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D007135:Immunoglobulin Variable Region; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D004254:DNA Nucleotidyltransferases; D045567:VDJ Recombinases; D001616:beta-Galactosidase