The 5' part of the mouse immunoglobulin kappa locus as a continuously cloned structure

Five contigs of the 5' part of the immunoglobulin kappa locus (F. Roschenth aler et at., fur: J. Immunol. 1999. 29: 2065-2071) have been linked by cosm id clones prepared from bacterial artificial chromosomes (BACs) and by PCR. One of the previously defined contigs which contains three pseudogenes (Z7 ) was shown by fluorescence in situ hybridization to be located near the ka ppa. locus on chromosome 6, but not within the locus; the three V kappa gen es are therefore now classified as orphons. A V kappa9/10 gene, which was s equenced previously, was now localized within the locus, and two additional Vs genes were identified, a potentially functional V kappa 24 gene and a p seudogene of the V kappa9/10 family. This brings the number of localized an d sequenced V kappa genes in the locus to 140; 75 of them are functional, 2 1 potentially functional and 44 pseudogenes. The 5' part of the Ic locus is now one contig of 1.88 megabase (Mb); it comprises 82 Vs genes. Other cont igs of the locus are 65 kb, 105 kb and 1.04 Mb in size and contain 2, 5 and 51 V kappa genes, respectively. The contigs are separated by three gaps of 10-40 kb each. Detailed restriction maps and other structural details of t he kappa locus are deposted in the Internet at http://www.med.uni-muenchen. de/biochemie/zachau/kappa.htm.