Organization and expression of the lambda-like genes that contribute to the mu-psi light chain complex in human pre-B cells.
Lambda-like genes encode a polypeptide chain that associates with VpreB and mu chain in the so-called mu-psi light chain complex specifically expressed in pre-B cells. In humans, the lambda-like gene cluster contains three genes, termed 14.1, 16.1, and F lambda 1. The 14.1 gene contains three exons and was previously sequenced. The 16.1 and F lambda 1 have been isolated from cosmid libraries. They both contain only the exons 2 and 3 that appear highly homologous to their 14.1 counterparts. The lambda-like gene cluster has been mapped on chromosome 22, close and distal to the BCR gene, in the order (14.1; F lambda 1) and 16.1. Hybridization with the 14.1 exon 1 probe did not detect an equivalent on 16.1 and F lambda 1 genes, but instead, only revealed the X6 gene, that was previously identified 5 kb upstream of the IGLC locus. It appears, therefore, that the gene organization of the lambda and lambda-like loci is strikingly similar, with a three-exon-containing gene 5' of a series of J lambda-C lambda or J lambda-C lambda-like tandemly organized genes. Analysis of the transcripts in a 8 week old human fetal liver clearly indicated that 14.1 was the only functional gene of the lambda-like cluster. Various forms of transcripts resulting from alternate splicing have been characterized. The major component consisted of a full-length (exons 1-2-3) mRNA, whereas a minor (1-3) transcript was identified. Only the full-length transcript could encode a functional polypeptide chain corresponding to the 22 kDa light chain surrogate.
Bossy
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Centre d'Immunologie INSERM-CNRS de Marseille-Luminy, France.
Milili
M
M
Zucman
J
J
Thomas
G
G
Fougereau
M
M
Schiff
C
C
D000595:Amino Acid Sequence; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D002874:Chromosome Mapping; D004247:DNA / Q000235:genetics; D004274:DNA, Recombinant; D005091:Exons; D005803:Genes, Immunoglobulin; D006412:Hematopoietic Stem Cells / Q000276:immunology; D006801:Humans; D007147:Immunoglobulin Light Chains; D054444:Immunoglobulin Light Chains, Surrogate; D007146:Immunoglobulin lambda-Chains / Q000235:genetics*; D007148:Immunoglobulin mu-Chains / Q000235:genetics*; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D012689:Sequence Homology, Nucleic Acid
D004274:DNA, Recombinant; D007147:Immunoglobulin Light Chains; D054444:Immunoglobulin Light Chains, Surrogate; D007146:Immunoglobulin lambda-Chains; D007148:Immunoglobulin mu-Chains; D008562:Membrane Glycoproteins; D004247:DNA