Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We determined the DNA sequence of two large regions of chromosome 22: 33.7 kb containing the C lambda complex; and 5.2 kb 5' of the functionally rearranged lambda gene from the human myeloma, U266. Analysis of these sequences reveals the complete structure of the human C lambda complex and a previously undescribed seventh C lambda region that may encode the Ke+Oz- lambda protein. The seven constant regions are organized in a tandem array, and each is preceded by a single J lambda region. lambda 1, lambda 2, lambda 3, and lambda 7 are apparently active genes, while lambda 4, lambda 5, and lambda 6 are pseudogenes. There are no other J lambda or C lambda regions within a 60-kb region surrounding the C lambda complex; however, there are at least four other lambda-like genes and lambda pseudogenes in the human genome. The lambda genes appear to have evolved via a series of gene duplication events resulting from unequal crossing over or gene conversion between the highly conserved C lambda regions on mispaired chromosomes. The lack of Alu sequences in this large segment of DNA suggests that the C lambda complex resulted from a recent amplification of a smaller Alu-free segment of DNA. Illegitimate recombination between repeated sequences containing lambda 2 and lambda 3 may be responsible for variable amplification of the lambda genes. We also found a 1,377-bp open reading frame (ORF) located on the opposite strand in the region containing lambda 7. While this ORF is flanked by potential RNA splicing signals, we have no evidence that it is part of a functional gene. We also discovered a V lambda pseudogene, called psi V lambda 1, 3 kb upstream of the U266 lambda gene. Using primer extension analysis to map the transcription start in the human lambda gene, we have identified its initiation point 41 bp upstream of the initiation codon. Analysis of the lambda promoter reveals that it contains a TATAA box at position -29 relative to the transcription initiation site and an octamer sequence at -67. Computer analysis of 40 kb of DNA sequences surrounding the human lambda locus has revealed no sequences resembling the kappa or IgH transcriptional enhancers, nor have in vitro analyses for function revealed enhancer activity. A comparison of these results with those obtained in separate studies with transgenic mice point to a complex, developmentally linked mechanism of transcriptional activation.
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PMID:Structure and expression of the human immunoglobulin lambda genes. 211 72

The human light chain JC lambda locus is comprised of seven distinct segments, designated JC lambda 1, JC lambda 2, JC lambda 3, JC lambda 4, JC lambda 5, JC lambda 6, and JC lambda 7. Whereas three of these seven represent pseudogenes (psi Clambda 4, psi C lambda 5, and psi C lambda 6), the JC lambda 1, JC lambda 2, and JC lambda 3 complexes are functional, as demonstrated by the finding of their protein products through sequence analyses of lambda-type Bence Jones proteins and light chains derived from monoclonal Igs. Although the JC lambda 7 segment also appears functional, as evidenced through analysis of lymphocyte-derived mRNA, heretofore no monoclonal JC lambda 7-containing lambda-chains have been identified. Serologically, two distinct isotypic markers, Mcg and Oz, are associated, respectively, with JC lambda 1 and JC lambda 3 proteins, in contrast to JC lambda2 components, which do not express these determinants and represent a third isotype. Although another serologic marker, Ke (Kern), considered a fourth isotype, has been assigned to the JC lambda 7 complex, this relationship has been questioned. We now report the primary structural features of a lambda-type Bence Jones protein that include the four distinctive residues encoded by the JC lambda 7 gene segment. This protein, obtained from a patient with multiple myeloma and designated MCP, represents the first example of such a molecule and provides definitive evidence that the JC lambda 7 gene complex is functional. Additionally, comparison of the C lambda sequences of Mcg-/Oz- Bence Jones proteins MCP and KERN supports the contention that the Ke-associated one-residue amino acid variation at position 152 reflects a C lambda A2 polymorphism and that yet another isotypic marker, provisionally designated Mcp, is encoded by the JC lambda 7 gene segment. Thus, we posit that there are four human JC lambda isotypes, Mcg, Ke-Oz-/Ke+Oz-, Ke-Oz+, and Mcp, that represent, respectively, products of the JC lambda 1, JC lambda 2, JC lambda 3, and JC lambda 7 gene complexes.
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PMID:Characterization of a light chain product of the human JC lambda 7 gene complex. 890 24