Immunoglobulin heavy chain germ-line JH-C mu transcription in human precursor B lymphocytes initiates in a unique region upstream of DQ52.
From human precursor B cells which had both immunoglobulin (Ig) heavy (H) chain loci in germ-line configuration, various IgH chain germ-line transcripts were isolated and sequenced. These transcripts were shown to contain sequences derived from the JH region, the IgH chain enhancer element or the Ig switch region. A number of isolated cDNA clones contained sequences at their 5' end that were derived from a single exon located just upstream of DQ52, designated the mu o' element. Sequence analysis of a 920-bp genomic DNA segment, containing the mu o' exon and its 5' flanking region, revealed the presence of various conserved motifs for DNA-binding proteins, such as E2A, Ets, NF-kappa B and AP-2, which have previously been found in the IgH and L chain enhancers. We propose that the activity of the mu o' element, resulting in germ-line transcription of the DQ52-JH gene segment, is required to generate full accessibility for the V(D)J recombinase.
Department of Immunohaematology, University Hospital Leiden, The Netherlands.
A
A
Thompson
E
E
Timmers
R K
RK
Schuurman
R W
RW
Hendriks
D001402:B-Lymphocytes / Q000737:chemistry* / Q000276:immunology; D001483:Base Sequence; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins; D005091:Exons; D005786:Gene Expression Regulation / Q000235:genetics; D015723:Gene Library; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D005803:Genes, Immunoglobulin / Q000235:genetics*; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis; D012045:Regulatory Sequences, Nucleic Acid; D014158:Transcription, Genetic / Q000235:genetics*; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D007143:Immunoglobulin Heavy Chains; D012333:RNA, Messenger