The organization of immunoglobulin variable kappa chain genes on mouse chromosome 6

One mouse with a known recombination (NAK) at the Igk locus on chromosome 6 and two new recombinants [B6.PL (7 NS) and B6.PL (85NS)] were examined using a series of probes, each of which is specific for a set of immunoglobulin (Ig) Vk genes. Under high stringency conditions, each probe detects from 1 to 19 Bam HI restriction endonuclease fragments (REFs) in genomic DNA by Southern transfer hybridization techniques. Analysis of the REF patterns indicate that the NAK recombination event occurred within the variable region of Igk. The REF patterns of the two B6.PL congenic mice provided two additional recombination events which could be examined. Although some of the REFs had shared mobility among the parental strains, at least 1 and up to 13 polymorphic REFs were present for a given probe among the NZB and AKR parental strains. The results from the NAK mouse indicate that at least some members of Vk4, Vk8, Vk10, and Vk21 were on one side of the recombination event linked to the Lyt-2 ^a and Igk-Efl ^a alleles of AKR, while the Vk9, Vk11, and Vk24 REF patterns came from the NZB parental strain linked to the Igk-Ef2 ^b (Vk1) allele. The two B6.PL congenics produced a refined map on the Lyt-2, Lyt-3 side of the Vk region. The B6.PL (85NS) mice retained the Vk21 REF pattern of the Lyt-2 ^a, Lyt-3 ^a donor strain PL/J, while displaying the C57BL/6 REF pattern for the other Vk gene groups tested. The B6.PL (75NS) mice retained the REF patterns of PL/J for Vk21 and Ef-1, indicating a third recombination. This indicates the Vk gene order is (Lyt-2; Vk21); Ef-1; (Vk4; Vk8; Vk10); and (Vk9; Vk11; Vk24; Ef-2).     

A yeast artificial chromosome contig spanning the mouse immunoglobulin kappa light chain locus

 A single contig spanning the entire mouse immunoglobulin kappa light chain (Igk) locus on chromosome 6 has been established using yeast and bacterial artificial chromosome clones. Detailed mapping of the Igk locus indicates that a member of the Igk-V2 gene family, located about 3.5 megabases upstream of the Igk-J-C complex, is the most distal functional Igk-V gene. Sequence analyses of Igk-V genes and anonymous DNA segments provide indications for internal duplications at the 5′ end of the Igk-V locus and identify the likely origin of Igk-V orphon gene clusters located elsewhere in the mouse genome. Received: 17 July 1996 / Revised: 2 September 1996     

The Mos proto-oncogene maps near the centromere on mouse chromosome 4

The Mos proto-oncogene, the cellular homolog of the transforming gene of Moloney murine sarcoma virus, was originally assigned to mouse chromosome 4 using independent panels of mouse/hamster somatic cell hybrids. By in situ hybridization to metaphase chromosomes and standard genetic backcrosses, we have confirmed this assignment and determined that Mos maps near the centromere in a region devoid of other markers. We have also identified a restriction fragment length polymorphism (RFLP) that defines two alleles of the Mos locus in selected inbred strains of laboratory mice. Using the RFLP, we determined the strain distribution pattern for the Mos gene in three sets of recombinant inbred strains and in five strains congenic for histocompatibility antigen genes localized on chromosome 4. These results establish Mos as a useful marker in a poorly characterized region of the mouse genome. In addition, these results will facilitate the genetic analysis of the Mos locus.     

Recombination between kappa chain genetic markers in the mouse

In this study we report the first instance of recombination between kappa chain genetic markers in the mouse. The recombination frequency, 0.45% (95% limits, 0.12–1.61), is similar to that previously found for recombination between the kappa chain locus and the Lyt-2, 3 locus (0.3%, 95% limits, 0.05–1.6), but is relatively low in comparison with that found at the heavy chain locus (0.41–5.4%). Lyt-2, 3-typing of the recombinants permits a partial ordering of the kappa chain and Lyt-2, 3 loci as (Lyt-2, 3, Igk-Ef1) - Igk-Ef2. Light chains controlled by the two kappa markers include the V_k-(ser) subgroup (controlled by Igk-Ef1) and V_k–1 (controlled by Igk-Ef2). One of the recombinants has been recovered in a homozygous state (NAK) and should be suitable for V _k gene mapping studies.Abbreviations C complement - C_H constant region of the Ig heavy chain - CI cytotoxicity index - DNP dinitrophenyl - FMF flow microfluorimetry - IEF isoelectric focusing - IF immunofluorescence - Ig immunoglobulin - KLH keyhole limpet hemocyanin - V_H variable region of the Ig heavy chain - V_k variable region of the Ig kappa chain - V-region variable region     

The alpha 2 chain of type 1 collagen does not map to mouse chromosome 16 but maps close to the Met proto-oncogene on mouse chromosome 6

The gene locus for the alpha 2 chain of type 1 collagen (Cola-2) was previously assigned to chromosome 16. Here we demonstrate, utilising both somatic cell hybrid analysis and genetic linkage analysis, in an interspecific Mus domesticus x Mus spretus cross that Cola-2 fails to cosegregate with mouse chromosome 16, but is linked to the Met proto-oncogene on chromosome 6.     

Two rearranged immunoglobulin kappa light chain genes in one mouse myeloma.

The organization of immunoglobulin gene segments coding for kappa light chains has been studied in uncloned and cloned DNA from mouse liver and a mouse myeloma. It is known that the C (constant, ref. 2) gene segment is present in the tumor DNA on two EcoRI fragments of 14 and 20 kb and in liver DNA on a 15 kb fragment. The 14 kb myeloma and the 15 kb liver fragment have been cloned previously. Here we report on the cloning of the 20 kb myeloma fragment and present detailed restriction maps covering about 22 kb of DNA surrounding the C gene segment in liver and tumor DNA. The region on the 20 kb fragment has been localized where a DNA rearrangement had occurred. The presence of two rearranged kappa light chain genes in one tumor is discussed in regard to the molecular basis of allelic exclusion.     

Evolutionary relationship between human and mouse immunoglobulin kappa light chain variable region genes

Similar to the Igh-V multigene family, the human or mouse Igk-V repertoirer is a distorted continuum of homologous genes that may be grouped into families displaying >80% nucleic acid sequence similarity among their members. systematic interspecies sequence comparisons reveal that most human Igk-V gene families exhibit clear homology to mouse Ogk-V families (sequence similarity >74%). A hypothetical phylogenetic tree of Igk-V genes predicts that a minimum of seven Igk-V genes/families predate mammalian radiation. In two cases, several interrelated mouse Igk-V families exhibit phylogenetic equidistance with just one human Igk-V family, implying a more pronounced divergence for the elevated number of Igk-V gene families in the mouse. Mouse-human Igk-V comaprisons, moreover, illustrate how expansion, contraction, and perhaps deletion of Igk-V gene families shape the Igk-V repertoire during mammalian evolution.     

The peripherin gene maps to mouse chromosome 15

We have mapped the mouse peripherin gene, Prph, to chromosome 15 by means of Southern analysis of a panel of Chinese hamster/mouse somatic cell hybrids using a rat peripherin cDNA probe. Peripherin is a recently characterized type III intermediate filament expressed in the peripheral and the central nervous system. Although its exact function is not known, peripherin is likely to be involved in the neuronal cytoskeleton, a role it shares with other intermediate filaments, such as the neurofilament proteins. The intermediate filament gene family is believed to have evolved via gene duplication and dispersal throughout the genome; these processes have resulted in clusters of intermediate filament genes on specific chromosomes and conservation of these chromosomal locations among mammalian species.     

Shiverer gene maps near the distal end of chromosome 18 in the house mouse

Several mouse mutations cause unstable locomotion, tremor, seizures, and a reduced lifespan because of deficient myelin formation in the central nervous system. Mutant alleles at the shiverer (shi) locus are the only ones in this series with a selective molecular defect, namely, in myelin basic proteins (MBPs), which are virtually absent in shi homozygotes and 50% reduced in heterozygotes. In the present study, backcross and intercross matings indicate recombination of 21.2 +/- 3.3% between myelin deficient, shimld, and fused phalanges, syfp, a marker near the middle of chromosome 18. Recombination of shimld with twirler (Tw), a marker near the centromere, is 45.7 +/- 4.9%. Thus, the shi locus maps near the distal end of mouse chromosome 18 and is the first available marker for this region. Given the evidence of other workers that an MBP locus maps to the same mouse chromosome, and that part of this chromosome may be syntenic with an MBP-PEPA region on human chromosome 18, it is likely that shi is in or near an MBP gene.     

Untranslated immunoglobulin kappa light chain mRNA in a lambda light chain-producing mouse myeloma, MOPC104E

Fourteen clones were isolated in culture from a mouse myeloma, MOPC104E. All clones had kappa and lambda types of light chain mRNAs in approximately equimolar quantity as assayed by hybridization with specific complementary DNA (cDNA). However, the myeloma produces and secretes only lambda-type light chain protein. Both kappa- and lambda-type mRNAs in these clones were indistinguishable from kappa- and lambda-type mRNAs of other myelomas with respect to (a) adsorption to oligo-(dT) cellulose, (b) molecular size (12.6 S), and (c) thermal stability of the hybrids formed with corresponding cDNA. The kappa chain mRNA of MOPC104E cells, however, was translated very inefficiently both in vivo and in vitro, whereas the lambda chain mRNA was translated efficiently. These results indicate that each cell of MOPC104E myeloma synthesizes a crippled kappa chain mRNA in addition to a normal lambda chain mRNA.     

Cloning of immunoglobulin kappa light chain genes from mouse liver and myeloma MOPC 173

The organization of the kappa chain constant region gene was compared in DNA from an immunoglobulin-producing mouse myeloma (MOPC 173) and from liver. In situ hybridization using the Southern blotting technique revealed constant region gene-containing EcoRI-DNA fragments of 14 and 20 kb in the myeloma tissue whereas one EcoRI-DNA fragment with a length of 15 kb was found in liver DNA. After enrichment by RPC-5 chromatography and preparative electrophoresis the 14 kb fragment from MOPC 173 DNA and the 15 kb fragment from liver DNA were cloned in the bacteriophage lambda vector Charon 4A using in vitro packaging. Extensive characterization of the two fragments by restriction endonuclease mapping, in situ hybridization, and electron microscopy (R-loop and heteroduplex) showed that both fragments contain the constant region but no MOPC 173 variable region gene. Both fragments are homologous over a length of 12.5 kb including the constant region but differ from one another starting about 2.7 kb from the 5' end of the constant region gene. This indicates that the 14 kb EcoRI-DNA fragment from the myeloma tissue clearly resulted from somatic DNA rearrangement although it does not seem to carry the MOPC 173 variable region gene. These observations suggest that somatic DNA rearrangement of immunoglobulin light chain genes can involve both homologous chromosomes.Images