Kyoko Ohno

A molecular genetic linkage map of mouse chromosome 19, including thelpr, Ly-44, andTdt genes

The mouselpr gene, which is an autosomal recessive gene causing autoimmune disease with features of human systemic lupus erythematosus and eventually death from severe immune-complex glomerulonephritis, has been mapped on chromosome 19. To determine its exact chromosomal location, a three-point backcross was carried out by mating (MRL/MpJ-lpr/lpr × MOL-MIT)F1 × MRL/MpJ-lpr/lpr using the genesLy-44 (lymphocyte differentiation antigen-44) andTdt (terminal deoxynucleotidyl transferase) as markers. The following order of genes is proposed, with the distances between genes given in parentheses: centromere-Ly-44 (19.3 cM)-lpr (6.1 cM)-Tdt-telomere. TheLy-44a andTdta alleles are found in all laboratory strains and in the wild Western European subspecies,domesticus andbrevirostris. In contrast, theLy-44b andTdtb alleles are found in some Asian subspecies, Chinese mice of wild origin,yamashinai andmolossinus. Furthermore the thirdTdt allele,Tdtc, is detected incastaneus.

A molecular genetic linkage map of mouse chromosome 18, includingspm, Grl-1, Fim-2/c-fms, andMbp

Restriction endonuclease fragment length variations (RFLV) were detected in mice with DNA probes for myelin basic protein (Mbp), glucocorticoid receptor-1 (Grl-1), and Friend MuLV integration site-2 (Fim-2). RFLV of theMbp gene were found inSacI restriction patterns, RFLV of theGrl-1 gene were found inEcoRV patterns, and RFLV of theFim-2 were found inBglII patterns. A three-point backcross was carried out by the backcross mating (C57BL/KsJ-spm/spm × MOL-MIT)F1 males × C57BL/KsJ-spm/spm; spm is an autosomal recessive gene causing sphingomyelinosis. From the results,spm, Grl-1, Fim-2, andMbp loci were mapped on chromosome 18, and the following order of genes is proposed, with distances between genes in parentheses: centromere—spm—(7.8 cM)—Grl-1—(7.8 cM)—Fim-2—(39.1 cM)—Mbp—telomere. All laboratory strains and two European subspecies (Mus mus domesticus andM. m. brevirostris) carry theGrl-1a,Fim-2a, andMbpa alleles. In contrast, another wild subspecies from Europe (M. m. musculus) and some Asian subspecies (M. m. molossinus, Chinese mice of wild origin, andM. m. yamashinai) carry theGrl-1b,Fim-2b, andMbpb alleles. Onlycastaneus strains carry the intermediate combination of theGrl-1b,Fim-2a, andMbpb alleles.

Mapping of the Hox-3.1 and Myc-1.2 genes on chromosome 15 of the mouse by restriction fragment length variations.

Restriction endonuclease fragment length variations (RFLV) were detected by use of the cDNA probeHox-3.1 for the homeo box-3.1 gene and also thec-myc oncogene probe for exon 2. RFLV ofHox-3.1 were found inHindIII restriction patterns, and RFLV of theMyc-1.2 gene inEcoRV patterns. From the RFLV, theHox-3.1 andMyc-1.2 genes were mapped on chromosome 15. Three-point cross test data showed that the frequency of recombination is 26.4% betweenMyc-1.2 andGpt-1, 30.2% betweenGpt-1 andGdc-1, and 9.4% betweenGdc-1 andHox-3.1. The following order of these genes is proposed,Myc-1.2—Gpt-1—Gdc-1—Hox-3.1. All laboratory strains carry theHox-3.1a andMyc-1.2a alleles. Among strains of wild origin,domesticus strains carry only theHox-3.1a andMyc-1.2a alleles, as do the laboratory strains. One strain ofbrevirostris carries theHox-3.1a andMyc-1.2b alleles. Other wild subspecies from Europe and Asia,M. m. musculus, M. m. castaneus, M. m. molossinus, Chinese mice of wild origin, andM. m. yamashinai carry theHox-3.1b andMyc-1.2b alleles.

Restriction fragment length variations and chromosome mapping of two mouse metallothionein genes,Mt-1 andMt-2

Restriction endonuclease fragment length variations (RFLVs) were found through the use of cDNA probes for metallothionein genes 1 (Mt-1) and 2 (Mt-2) in the mouse. RFLVs were detected in restriction patterns generated byBglII andXbaI in theMt-1 gene and byPvuII in theMt-2 gene. All laboratory strains carry theMt-1a andMt-2a alleles. Among strains of wild origin, some Western European subspecies (Mus mus domesticus andM. m. brevirostris) also carry theMt-1a andMt-2a alleles. In contrast, a European subspecies (M. m. musculus) and the great majority of subspecies from East Asian countries (M. m. molossinus, Chinese mice of wild origin, andM. m. yamashinai) carry theMt-1b andMt-2b alleles. Adomesticus strain from Bulgaria and twocastaneus strains from Thailand and Philippines carry the intermediate combination ofMt-1b andMt-2a alleles. Using the RFLVs, we mapped theMt-1 andMt-2 genes on chromosome 8, and they appear to be very closely linked since no recombination was observed between them in any of the mice examined. Data from three-point cross tests showed that the recombination frequencies are 4.31% betweenOs andMt, 15.52% betweenMt andPrt-2, and 19.83% betweenOs andPrt-2. The gene order ofOs-Mt-1,Mt-2-Prt-2 has been confirmed.

Autosomal Recessive Polycystic Kidney in Rats

We evaluated the characteristics of renal lesions in rat autosomal recessive polycystic kidney (ARPK). In rat ARPK, small cysts appeared primarily in the medulla 2 months after birth and gradually extended to the cortex, forming large cysts involving the entire layer after 8 months. By immunofluorescence microscopy, type IV collagen was more strongly stained in the epithelial basement membrane of the rat ARPK than in the normal rat tubular basement membrane (TBM). Electron microscopy demonstrated a marked thickening, slight splitting and lamination of the TBM in the ARPK. As peroxidase-labeled lectins, dolichos biflorus very strongly stained the cyst epithelium whereas lens culinaris did not. These findings indicate that cysts in rat ARPK originate in the collecting duct.

Genetic mapping of genes regulating the thymus size in back‐cross rats between the laboratory BUF/Mna strain and the MITE strain derived from the wild rat, Rattus norvegicus

The thymoma prone BUF/Mna (B) rat is a useful model for Studying the genes responsible for thymus enlargement during the stage of young growth. Among the strains of rats, B rats have the largest thymuses at al stages of life. A locus, Ten‐1, which contributes to thymus enlargement in back‐cross (BC) rats between the B and WKY/NCrj (W) strains, was mapped on chromosome 1. To determine the precise location of the bus, (B×(B×MITE)F1) BC rats were generated by crossing the B strain with the Inbred MITE (M) strain, which was established from captured, Japanese wild rats, and were examined by linkage study using polymerase chain reaction with 67 microsatellite markers. Linkages with thymus enlargements were found In genotypes of seven markers, BSIS, LSN, MYL2, IGF2, PBPC2, D1Mgh11, and D1Mit6, by X2‐test and Students t‐test, which confirmed the presence of the genetic locus associated with thymus enlargement, Ten‐1, in this region. Paradoxically, a suppressive locus, Tsu‐1, to thymus enlargement was also found on chromosome 3, showing linkages of phenotype of the small thymus with genotypes of SCN2A, CAT D3Mit16, and D3Mit13. By analyses of mapmaker/exp and mapmaker/qtl, Ten‐1 was mapped at 4.6 cM proximal from IGF2 locus on chromosome 1 and Tsu‐1 at 4.0 cM proximal from CAT locus on chromosome 3, respectively.

A new allele at the lpr gene on mouse Chromosome 19 expresses properties different from the original recessive mutation

aDepartment of Biochemistry, Institute for Developmental Research, Aichi Prefecture Colony, Kamiyacho, Kasugai, Aichi 480-03, Japan 2Laboratory of Experimental Animals, Yagi Memorial Park, Mitake, Gifu 505-01, Japan 3Research Laboratories, Nippon Shinyaku Co., Sakanotsujicbo, Oyake, Yamashinaku, Kyoto 607, Japan 4Laboratory Animal Research Center, Institute of Medical Science, University of Tokyo, Tokyo 108, Japan

A molecular genetic linkage map of mouse chromosome 10, including the Myb, S100b, Pah, Sl, and Ifg genes.

Restriction endonuclease fragment length variations (RFLV) on mouse chromosome 10 were detected in four genes, namely, theMyb protooncogene (Myb) and the genes for S100β protein (S100b), phenylalanine hydroxylase (Pah), and interferon-γ (Ifg). RFLV were found in restriction patterns generated withBamHI forMyb, in those generated withBglII forS100b, in those generated withEcoRV forPah, and in those generated withTaqI forIfg. A multipoint backcross was carried out by the mating (129/Sv-Sl/+ × MOL-MIT)F1 × 129/SvJ-+/+. TheSl mutation has phenotypic effects which include deficiencies in pigment cells, germ cells, and blood cells. The following order of genes was derived from the results of the multipoint backcross, with distances between genes in parentheses: centromere—Myb—(34.9 cM)—S100b—(8.5 cM)—Pah—(8.5 cM)—Sl—(12.3 cM)—Ifg—telomere. Most laboratory strains and two strains ofMus musculus domesticus of wild origin carry theMyba, S100a, Paha, andIfga alleles. In contrast, a strain ofM. m. musculus, two strains ofM. m. yamashinai, and two strains ofM. m. molossinus carry theMybb, S100b, Pahb, andIfgb alleles. Other strains of wild origin carry various combinations of these alleles.

Cystic Basement Membrane with Increased Negative Charge in Rat Autosomal Recessive Polycystic Kidney

Cystic Basement Membrane with Increased Negative Charge in Rat Autosomal Recessive Polycystic Kidney Z. Zenshiro Inage Y. Yumio Kikkawa M. Motoyuki Minato M. Misao Owada T. Teruo Kitagawa K. Kyoko Ohno K. Kyoji Kondo Y. Yoshihiko Ueda K. Kazunari Iidaka Department of Pediatrics, Nihon University, School of Medicine, Tokyo; Laboratory of Experimental Animals, Yagi Memorial Park, Gifu; Second Department of Pathology, Dokkyo University, School of Medicine Tochigi, Japan