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IMGT unique numbering for all IG and TR V-REGIONs of all species:
interest for structure and evolution

Citing IMGT unique numbering for V-REGION: Lefranc, M.-P. et al., Dev. Comp. Immunol., 27, 55-77 (2003) PMID: 12477501 pdf

In order to easily compare V-REGION sequences of IG and TR from all species, a unique numbering has been defined by Marie-Paule Lefranc [1-6].

The 'IMGT unique numbering' concept is part of the 'NUMEROTATION' concept of IMGT-ONTOLOGY [7]

The IMGT unique numbering for all IG and TR V-REGIONs of all species relies on the high conservation of the structure of the variable region [1-6]. This numbering, set up after aligning more than 5 000 sequences, takes into account and combines the definition of the framework (FR) and complementarity determining regions (CDR) [8], structural data from X-ray diffraction studies [9], and the characterization of the hypervariable loops [10]. The delimitations of the FR-IMGT and CDR-IMGT regions have been defined and Correspondence between the IMGT unique numbering and the other numberings has been established [6].

The IMGT unique numbering has many advantages:

By facilitating comparisons between the sequences and the descriptions of alleles and mutations, the IMGT unique numbering represents a big step forward in the analysis of the IG and TR sequences of all species. Moreover, it gives in-sight in the structural configuration of the variable domain and opens interesting views on the evolution of the sequences of the V-set, since this numbering has been applied with success to all the sequences belonging to the V-set of the immunoglobulin superfamily, including nonrearranging sequences in vertebrates (CD4, Xenopus CTX,...) and in invertebrates (Drosophila Amalgam, Drosophila Fasciclin II, etc.) [1, 2, 9].

References:
[1] Lefranc, M.-P., "Unique database numbering system for immunogenetic analysis", Immunology Today, 18, 509 (1997), LIGM:194.
[2] Lefranc, M.-P., "IMGT Locus on Focus: A new section of Experimental and Clinical Immunogenetics", Exp. Clin. Immunogenet., 15, 1-7 (1998) PMID: 9619395, LIGM:199 pdf
[3] Lefranc, M.-P., "The IMGT unique numbering for immunoglobulins, T cell Receptors and Ig-like domains", The Immunologist, 7, 132-136 (1999), LIGM:217 pdf
[4] Lefranc, M.-P. and Lefranc, G., The Immunoglobulin FactsBook, Academic Press, 458 pages (2001) ISBN:012441351X.
[5] Lefranc, M.-P. and Lefranc, G., The T cell receptor FactsBook, Academic Press, 398 pages (2001) ISBN:0124413528.
[6] Lefranc, M.-P. et al., Dev. Comp. Immunol., 27, 55-77 (2003) PMID: 12477501, LIGM:268 pdf with permission from Elsevier
[7] Giudicelli, V. and Lefranc, M.-P., Bioinformatics, 15, 1047-1054 (1999) PMID: 10745995, LIGM:221 pdf
[8] Kabat, E.A. et al. in "Sequences of Proteins of Immunological Interest" Public Health Service, NIH, Washington D.C. (1987).
[9] Satow, Y. et al., J. Mol. Biol., 190, 593-604 (1986).
[10] Chothia, C. and Lesk, A.M., J. Mol. Biol., 196, 901-917 (1987).
[11] Pommié, C. et al., J. Mol. Recognit., 17, 17-32 (2004), PMID: 14872534, LIGM:284.
[12] Ruiz, M. and Lefranc, M.-P. Immunogenetics, 53, 857-883 (2002) PMID: 11862387 LIGM:259
Acnowledgements:
We thank Elsevier and Developmental and Comparative Immunology, for allowing IMGT to make available the DCI pdf file on the IMGT site.