IGL@ explained

Immunoglobulin lambda locus, also known as IGL@, is a region on the q arm of human chromosome 22, region 11.22 (22q11.22) that contains genes for the lambda light chains of antibodies (or immunoglobulins).^[1]

Function

Immunoglobulins recognize foreign antigens and initiate immune responses such as phagocytosis and the complement system. Each immunoglobulin molecule consists of two identical heavy chains and two identical light chains. There are two classes of light chains, kappa and lambda. This region represents the germline organization of the lambda light chain locus. The locus includes V (variable), J (joining), and C (constant) segments. During B cell development, a recombination event at the DNA level joins a single V segment with a J segment; the C segment is later joined by splicing at the RNA level. Recombination of many different V segments with several J segments provides a wide range of antigen recognition. Additional diversity is attained by junctional diversity, resulting from the random additional of nucleotides by terminal deoxynucleotidyltransferase, and by somatic hypermutation, which occurs during B cell maturation in the spleen and lymph nodes. Several V segments and three C segments are known to be incapable of encoding a protein and are considered pseudogenes. The locus also includes several non-immunoglobulin genes, many of which are pseudogenes or are predicted by automated computational analysis or homology to other species.

Genes

The immunoglobulin lambda locus contains the following genes:

• IGLC@ – constant group
  • IGLC1 – immunoglobulin lambda constant 1 (Mcg marker)
  • IGLC2 – immunoglobulin lambda constant 2 (Kern-Oz- marker)
  • IGLC3 – immunoglobulin lambda constant 3 (Kern-Oz+ marker)
  • IGLC7 – immunoglobulin lambda constant 7
• IGLJ@ – joining group
  • IGLJn – immunoglobulin lambda joining n
  • IGLJ1, IGLJ2, IGLJ3, IGLJ6, IGLJ7
• IGLV@ – variable group
  • IGLVm-n – immunoglobulin lambda variable n-m
  • IGLV1-36, IGLV1-40, IGLV1-44, IGLV1-47, IGLV1-51, IGLV1-62
  • IGLV2-5, IGLV2-8, IGLV2-11, IGLV2-14, IGLV2-18, IGLV2-23
  • IGLV3-1, IGLV3-10, IGLV3-12, IGLV3-16, IGLV3-19, IGLV3-21, IGLV3-25, IGLV3-27
  • IGLV4-3, IGLV4-60, IGLV4-69
  • IGLV5-37, IGLV5-39, IGLV5-45, IGLV5-52
  • IGLV6-57
  • IGLV7-43
  • IGLV9-49
  • IGLV10-54

Ig lambda chain C regions is a protein that in humans is encoded by the IGLC2 gene.^[1]

Further reading

• Taussig MJ . Molecular genetics of immunoglobulins. . Immunology. Supplement . 1 . 7–15 . 1988 . 3133312 .
• Combriato G, Klobeck HG . V lambda and J lambda-C lambda gene segments of the human immunoglobulin lambda light chain locus are separated by 14 kb and rearrange by a deletion mechanism. . Eur. J. Immunol. . 21 . 6 . 1513–22 . 1991 . 1904362 . 10.1002/eji.1830210627 . 84668650 .
• Vasicek TJ, Leder P . Structure and expression of the human immunoglobulin lambda genes. . J. Exp. Med. . 172 . 2 . 609–20 . 1990 . 2115572 . 10.1084/jem.172.2.609 . 2188323 .
• Emanuel BS, Cannizzaro LA, Magrath I, etal . Chromosomal orientation of the lambda light chain locus: V lambda is proximal to C lambda in 22q11. . Nucleic Acids Res. . 13 . 2 . 381–7 . 1985 . 3923432 . 10.1093/nar/13.2.381 . 341002 .
• Hieter PA, Korsmeyer SJ, Waldmann TA, Leder P . Human immunoglobulin kappa light-chain genes are deleted or rearranged in lambda-producing B cells. . Nature . 290 . 5805 . 368–72 . 1981 . 6783958 . 10.1038/290368a0 . 1981Natur.290..368H . 4333721 .
• Erikson J, Martinis J, Croce CM . Assignment of the genes for human lambda immunoglobulin chains to chromosome 22. . Nature . 294 . 5837 . 173–5 . 1982 . 6795508 . 10.1038/294173a0 . 22056008 .
• McBride OW, Hieter PA, Hollis GF, etal . Chromosomal location of human kappa and lambda immunoglobulin light chain constant region genes. . J. Exp. Med. . 155 . 5 . 1480–90 . 1982 . 6802926 . 10.1084/jem.155.5.1480 . 2186665 .
• Frippiat JP, Williams SC, Tomlinson IM, etal . Organization of the human immunoglobulin lambda light-chain locus on chromosome 22q11.2. . Hum. Mol. Genet. . 4 . 6 . 983–91 . 1995 . 7655473 . 10.1093/hmg/4.6.983 .
• Williams SC, Frippiat JP, Tomlinson IM, etal . Sequence and evolution of the human germline V lambda repertoire. . J. Mol. Biol. . 264 . 2 . 220–32 . 1997 . 8951372 . 10.1006/jmbi.1996.0636 .
• Kawasaki K, Minoshima S, Nakato E, etal . One-megabase sequence analysis of the human immunoglobulin lambda gene locus. . Genome Res. . 7 . 3 . 250–61 . 1997 . 9074928 . 10.1101/gr.7.3.250 . free .
• Lefranc MP . Nomenclature of the human immunoglobulin lambda (IGL) genes. . Exp. Clin. Immunogenet. . 18 . 4 . 242–54 . 2002 . 11872955 . 10.1159/000049203 . 27255400 .
• Strausberg RL, Feingold EA, Grouse LH, etal . Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences. . Proc. Natl. Acad. Sci. U.S.A. . 99 . 26 . 16899–903 . 2003 . 12477932 . 10.1073/pnas.242603899 . 139241 . 2002PNAS...9916899M . free .
• Boursier L, Su W, Spencer J . Imprint of somatic hypermutation differs in human immunoglobulin heavy and lambda chain variable gene segments. . Mol. Immunol. . 39 . 16 . 1025–34 . 2003 . 12749909 . 10.1016/S0161-5890(03)00033-6 .
• Makino DL, Henschen-Edman AH, McPherson A . Four crystal forms of a Bence-Jones protein. . Acta Crystallographica Section F . 61 . Pt 1 . 79–82 . 2006 . 16508097 . 10.1107/S1744309104028532 . 1952397 .
• Richl P, Stern U, Lipsky PE, Girschick HJ . The lambda gene immunoglobulin repertoire of human neonatal B cells. . Mol. Immunol. . 45 . 2 . 320–7 . 2007 . 17675156 . 10.1016/j.molimm.2007.06.155 .

Notes and References

1. Web site: Entrez Gene: IGL@ immunoglobulin lambda locus.