Lawrence A. D'Hoostelaere

A glutaminase (gls) gene maps to mouse chromosome 1, rat chromosome 9, and human chromosome 2.

A rat cDNA clone encoding a portion of phosphate-activated glutaminase was used to identify DNA restriction fragment length polymorphisms (RFLPs) in sets of somatic cell hybrids and between wild-derived and inbred strains of mice. Segregation of rat and mouse chromosomes among somatic cell hybrids indicated assignment to rat chromosome 9 and mouse chromosome 1. Analysis of chromosome 1 alleles for several genes in an interspecific cross between Mus spretus and C3H/HeJ-gld/gld mice indicates that glutaminase can be positioned within 5.5 +/- 2.0 cM proximal to Ctla-4. Similarly, human-hamster somatic cell hybrids were examined for RFLPs, and four human EcoRI restriction fragments were found to hybridize with the rat glutaminase probe. Two of these restriction fragments cosegregated and mapped to human chromosome 2 in a region that is syntenic with mouse chromosome 1 and rat chromosome 9.

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-2a and Igk-Efla alleles of AKR, while the Vk9, Vk11, and Vk24 REF patterns came from the NZB parental strain linked to the Igk-Ef2b (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-2a, Lyt-3a 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).

Mapping of the bcl-2 oncogene on mouse chromosome 1.

Two bcl-2 alleles have been identified in inbred strains of mice by restriction fragment length polymorphism (RFLP). Analysis of a bcl-2 RFLP in a series of bilineal congenic strains (C.D2), developed as a tool for chromosomal mapping studies, revealed linkage of bcl-2 to the Idh-1/Pep-3 region of murine chromosome 1. The co-segregation of bcl-2 alleles with allelic forms of two other chromosome 1 loci, Ren-1,2 and Spna-1, in a set of back-cross progeny, positions bcl-2 7.8 cM centromeric from Ren-1,2.

Allelic variants of Ly-5 in inbred and natural populations of mice.

Allelic variants of Ly-5 in inbred commensal and other natural populations of mice were analyzed by patterns of restriction fragment length polymorphisms (RFLP) and Southern hybridization using an Ly-5 cDNA probe and by cell-surface staining with a panel of antibodies directed against polymorphic and nonpolymorphic Ly-5 determinants. New Ly-5 alleles were defined by RFLPs generated by both Eco RI and Bam HI restriction enzyme digests. The Mus musculus subspecies and other species within the genus Mus showed a strong correlation between allelic variants defined by restriction enzymes and serologic specificities. The data also suggest the conservation of the Ly-5 gene throughout the genus Mus.

Mapping of alpha-spectrin on distal mouse chromosome 1

DNAs from different strains of inbred mice and feral Mus spretus were found to exhibit restriction fragment length polymorphisms (RFLP) when hybridized with a probe prepared from a c-DNA clone of the mouse alpha-spectrin (Spna-1) gene. Studies of five recombinant inbred strains and (C57BL/6 X M. spretus) F1 X C57BL/6 backcross mice demonstrated that these RFLPs were allelic and that Spna-1 is closely linked to Ly-9 and Ly-17 on the distal region of chromosome 1.

Localization of CT beta and C kappa on mouse chromosome 6.

In the mouse three lymphocyte gene families have been positioned on the proximal region of chromosome 6. Originally the immunoglobulin kappa light chain (Igk) and the thymocyte surface antigens Lyt-2 and Lyt-3 were assigned to chromosome 6, and recently the beta chain of the T-cell receptor for antigen was positioned proximal to Igk. Molecular clones which recognize the constant (C region of the beta chain of the T-cell receptor for antigen (CTβ) and the constant region of the immunoglobulin kappa (Ck) chain were used to determine recombination frequencies with respect to the morphological marker hypodactyly (Hd). SJL/JLw π mice were mated with C.B6.C3-Hd/+ mice, and the progeny expressing the Hd phenotype were mated with SJL/JLw π mice. Backcross progeny which expressed the Hd phenotype were nephrectomized, and kidney DNA was examined by Southern hybridization for the polymorphic restriction endonuclease fragment (REF) patterns of the parental mice. Of the 88 progeny tested in this three-point cross, 3 CTβ and 4 CK homozygote REF patterns were detected. These homozygotes were mutually exclusive. This implies the following gene order: centromere-CTβ-Hd-Igk and CTβ1 would be 7.95±2.88 centimorgans from CK.

Mapping of the Ly-4 (L3T4) T-cell differentiation antigen on mouse chromosome 6 by the use of RFLPs in an interspecific cross

1 Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA 2 Laboratory of Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA 3 Cellular Immunology Section, National Institutes of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA 4 Department of Medicine, Division of Immunology, Stanford University Medical Center, Stanford, CA 94305, USA 5 Laboratory of Immunopathology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA

T-cell receptor VTβ genes in natural populations of mice

The composition of 15 VTβ gene subfamilies has been examined by Southern hybridization among a broad spectrum of colony bred rat and mouse species extending phylogenetically from Rattus to Mus musculus domesticus. Most mouse species contain a similar content of VTβ genes as determined by the number of hybridizing restriction fragment (RF) bands. Furthermore, the extent of restriction fragment length polymorphism (RFLP) appears to be limited. Some VTβ gene families, however, are missing from Rattus (VTβ7, VTβ12) and M. shortridgei (VTβ9, VTβ16). Extension of the VTβ survey to a panel of 38 wild-caught mice reveals that nearly a third lack specific hybridization to the VTβ5 probe. Previous reports have established that the mouse inbred strains SJL, C57BR, C57L, and SWR lack 50% of their VTβ repertoire, including VTβ5 (Behlke et al. 1985). This study demonstrates that natural populations of mice also carry a significantly reduced VTβ gene repertoire.

The context of T-cell receptor gamma chain genes among wild mouse species.

We have examined the context of mouse T-cell receptor gamma (Tcr γ) chain variable (V γ) and constant (Cγ) genes among a panel of geographically isolated species of mice. Our Southern hybridization survey with Cγ reveals that essentially three Cγ genes are found among mouse species extending phylogenetically from inbred mice through the feral species Mus pahari. However, a V γ DNA probe detects three to nine V γ restriction fragment bands among the same group of mice. These results suggest that certain feral mice such as M. pahari, M. platythrix, and M. shortridgei have amplified numbers of V γ genes. Studies of individual mice from these particular species indicate the highly amplified V γ content is not the result of a catastrophic gene duplication or deletion event. We conclude that certain species of mice maintain increased content of V γ presumably for increased diversity in a Tcell response.

Localization of CTβ and CK on mouse chromosome 6

In the mouse three lymphocyte gene families have been positioned on the proximal region of chromosome 6. Originally the immunoglobulin kappa light chain (Igk) and the thymocyte surface antigens Lyt-2 and Lyt-3 were assigned to chromosome 6, and recently the beta chain of the T-cell receptor for antigen was positioned proximal to Igk. Molecular clones which recognize the constant (C region of the beta chain of the T-cell receptor for antigen (CTβ) and the constant region of the immunoglobulin kappa (Ck) chain were used to determine recombination frequencies with respect to the morphological marker hypodactyly (Hd). SJL/JLw π mice were mated with C.B6.C3-Hd/+ mice, and the progeny expressing the Hd phenotype were mated with SJL/JLw π mice. Backcross progeny which expressed the Hd phenotype were nephrectomized, and kidney DNA was examined by Southern hybridization for the polymorphic restriction endonuclease fragment (REF) patterns of the parental mice. Of the 88 progeny tested in this three-point cross, 3 CTβ and 4 CK homozygote REF patterns were detected. These homozygotes were mutually exclusive. This implies the following gene order: centromere-CTβ-Hd-Igk and CTβ1 would be 7.95±2.88 centimorgans from CK.