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Immunogenetics

, Volume 46, Issue 4, pp 283–292 | Cite as

Genomic organization of the sheep immunoglobulin JH segments and their contribution to heavy chain variable region diversity

  • Vinciane Dufour
  • François Nau
ORIGINAL PAPER

Abstract

 The sheep immunoglobulin heavy chain Igh-J locus has been characterized in order to determine the genomic organization of JH segments and their contribution to heavy chain diversity. The locus contains six segments, of which two are functional and four are apparently pseudogenes. These segments span a 1.8 kilobase (kb) region. The distance between JH-ps4 (the 3′-most segment) and the first domain of the μ-chain encoding constant gene is about 5 kb. The two functional JH segments have a standard upstream recombination signal sequence, including heptamer and nonamer sequences separated by a 22–23 nucleotide spacer, and end with a RNA donor splice site. These two segments possess all the characteristic JH invariant residues and are found in expressed μ heavy chain variable regions. The 5′ functional JH1 segment is used in more than 90% of the cDNAs sequenced to date. The contribution of JH segment germline multiplicity to variable regions diversity appears therefore to be minimal. Comparison with other mammalian JH segments shows that all loci are very closely related and probably have evolved from a common ancestral locus.

Keywords

Heavy Chain Splice Site Genomic Organization Donor Splice Donor Splice Site 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Vinciane Dufour
    • 1
  • François Nau
    • 1
  1. 1.IBMIG, Laboratory of Molecular Immunology, CNRS ESA 6031, University of Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, FranceFR

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