Chromosomal localization of the major histocompatibility complex in cattle and river buffalo by fluorescent in situ hybridization.
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Biomedical subjects
Publications and source records attributed to L C Skow.
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A phage library of bovine genomic DNA was screened for hybridization with a human HSP70 cDNA probe, and 21 positive plaques were identified and isolated. Restriction mapping and blot hybridization analysis of DNA from the recombinant plaques demonstrated that the cloned DNAs were derived from three different regions of the bovine genome. One region contains two tandemly arrayed HSP70 sequences, designated HSP70-1 and HSP70-2, separated by approximately 8 kb of DNA. Single HSP70 sequences, designated HSP70-3 and HSP70-4, were found in two other genomic regions. Locus-specific probes of unique flanking sequences from representative HSP70 clones were hybridized to restriction endonuclease-digested DNA from bovine-hamster and bovine-mouse somatic cell hybrid panels to determine the chromosomal location of the HSP70 sequences. The probe for the tandemly arrayed HSP70-1 and HSP70-2 sequences mapped to bovine chromosome 23, syntenic with glyoxalase 1, 21 steroid hydroxylase, and major histocompatibility class I loci. HSP70-3 sequences mapped to bovine chromosome 10, syntenic with nucleoside phosphorylase and murine osteosarcoma viral oncogene (v-fos), and HSP70-4 mapped to bovine syntenic group U6, syntenic with amylase 1 and phosphoglucomutase 1. On the basis of these data, we propose that bovine HSP70-1,2 are homologous to human HSPA1 and HSPA1L on chromosome 6p21.3, bovine HSP70-3 is the homolog of an unnamed human HSP70 gene on chromosome 14q22-q24, and bovine HSP70-4 is homologous to one of the human HSPA-6,-7 genes on chromosome 1.
Steroid 15 alpha-hydroxylase (P45015 alpha) activity is concomitant with the expression of two types of mRNA in the mouse liver. Two discrete genes, designated 15 alpha oh-1 and 15 alpha oh-2, that encode the two mRNAs were recovered from total genomic libraries of the inbred mouse strains 129/J and C57Bl/6J and identified by cDNA hybridization, restriction-site analysis and partial nucleotide sequence. Both genes are approx. 9 kb long and share significant homology, including flanking regions, over a region of at least 30 kb. The two distinct 15 alpha oh genes are members of a larger family of homologous genes and/or pseudogenes of unknown function. The most extensive sequence homology among family members in the 3' portion of the gene with progressively less homology toward the 5' end. The far 5' portions of 15 alpha oh-1 and 15 alpha oh-2 are very similar to one another but there is no observed homology with other genes of the family. The two 15 alpha oh genes and the homologous family have been localized to mouse chromosome 7 by somatic cell hybrid mapping. Analysis of a restriction fragment length polymorphism in recombinant inbred mice shows a close linkage of 15 alpha oh-1 and 15 alpha oh-2 with the Coh locus.
Genomic DNAs from animals representing six breeds of cattle (Angus, Brahman, Hereford, Holstein, Jersey and Texas Longhorn) were screened with cloned gene probes in a search for restriction fragment length polymorphisms (RFLPs). Eleven RFLPs were identified using seven different probes: growth hormone, prolactin, osteonectin, alpha A-crystallin, gamma crystallin, fibronectin and 21-steroid hydroxylase. The frequencies of the alleles identified by each probe were calculated and compared in a limited sampling of the six bovine breeds. These polymorphisms greatly enhance the pool of immunogenetic, biochemical and molecular markers available in cattle for linkage analysis, testing of parentage, and distinction of breeds.
Spontaneous, malignant ovarian granulosa cell (GC) tumors occur in pubertal SWR and specific SWXJ recombinant inbred strains of mice. Treatment of these mice with dehydroepiandrosterone (DHEA), an adrenal secretory steroid with anticancer actions against spontaneous and carcinogen-induced tumors of different tissues, gave unexpected results. Diet supplemented with 0.4% DHEA (a) induced significantly more GC tumors in spontaneous tumor-susceptible strains (SWR and SWXJ-1, -4, and -9), (b) induced the first GC tumors observed in five previously tumor-free strains (SWXJ-6, -7, -8, -10, and -12), and (c) failed to induce GC tumors in SJL and in the remaining six SWXJ strains (SWXJ-2, -3, -5, -11, -13, and -14). The strain distribution pattern of DHEA-induced GC tumor susceptibility versus resistance was compared with strain distribution patterns for 35 different loci known to distinguish SWR and SJL progenitor strains. A complete match of DHEA-induced GC tumors with pancreas-2 (Pan-2) on mouse chromosome 4 was found. We have named this new locus GC tumor susceptibility (Gct), with the Gcts (susceptible) allele found in SWR and the Gctr (resistant) allele found in SJL mice. The Gct locus is closely linked to pancreas-2, Pan-2, but the order of genes is not yet confirmed. In addition, data from F1 progeny of matings between SWR and selected inbred strains provide suggestive evidence for a second gene controlling GC tumor incidence that we hypothesize involves steroid metabolism. Differences in GC tumor incidence data from reciprocal F1 progeny of matings between SWR and SJL mice reveal a strong maternal effect that may represent yet a third gene. These data support a heritable basis for GC tumorigenesis in the SWR model involving a small number of genes.
Restriction fragments analysis of DNA from mouse-hamster somatic-cell hybrid clones revealed that a mouse gamma crystallin cDNA hybridized to genomic sequences located on mouse chromosome 1. Identification of restriction fragment length polymorphisms (RFLPs) in the gamma crystallin sequences of inbred strains of mice permitted the further localization of the gamma crystallin genes (Cryg) to the proximal region of chromosome 1 closely linked to the loci encoding isocitrate dehydrogenase (Idh-1), a low molecular weight (LM) crystallin protein polymorphism (Len-1), and fibronectin (Fn-1). A single recombinant was observed between Len-1 and an RFLP in the gamma crystallin gene family, consistent with the hypothesis that Len-1 is one of the several structural loci encoding gamma crystallin genes. Len-1 is probably located on the centromeric end of the Cryg gene family. Linkage of Idh-1, Cryg, and Fn-1 in mice extends the syntenic relationship of those loci to the human, bovine, and rodent genomes and may define a chromosomal region that is generally conserved among mammals. The map position of Cryg, near the eye lens obsolescence (Elo) locus, was confirmed by the discovery that the restriction fragment patterns of gamma crystallin sequences differed between strain C3H/HeJ and the congenic anophthalmic mutant strain, C3H.Elo. Therefore, the gamma crystallin genes were cotransferred with the mutant Elo gene in the derivation of C3H.Elo. The results establish that LEN-1 is a marker for the gamma crystallin gene family, position the gamma crystallin gene family relative to other markers on mouse chromosome 1, and provide additional evidence that the Elo mutation is encoded at a locus closely linked to the gamma crystallin gene cluster. This study found no evidence of recombination hot spots within the gamma crystallin gene cluster.
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Synteny mapping of the genes for bovine alpha A crystallin (CRYA-1), steroid 21 hydroxylase (21OH), and a class I major histocompatibility locus bovine leukocyte antigen (BoLA) was accomplished by Southern blot analysis of DNA from bovine-hamster hybrid somatic cells. Comparison of the distribution patterns of CRYA-1, 21OH, and BoLA sequences among the hybrid cells revealed that the genes are located on two different chromosomes in the bovine genome. CRYA-1 mapped with superoxide dismutase (SOD1 in syntenic group U10, while 21OH and BoLA were concordant with glyoxylase (GLO1) in syntenic group U21. Therefore, the syntenic array of CRYA-1, 21OH, and BoLA in cattle is different from that observed in rodents, where the genes are closely linked to each other and to GLO1, and consistent with reported linkages in man.
DNAs from cow-hamster and cow-mouse somatic hybrid cells segregating bovine chromosomes have been analyzed by Southern blotting and hybridization with human fibronectin and gamma crystallin probes. Concordancy of retention of these bovine genes was compared to cattle isozyme loci representing previously described syntenic groups. Bovine fibronectin (FNI) and gamma crystallin (CRYG) fragments were concordant with each other and with isocitrate dehydrogenase 1 (IDH1), representing the bovine syntenic group U17. The syntenic relationship of these genes is conserved on human chromosome 2q and also on mouse chromosome 1. In addition, bovine RFLPs were identified with both fibronectin and gamma crystallin probes. These polymorphisms will be used to study recombination between the syntenic loci in pedigreed herds and to mark a segment of the bovine genome that is likely homologous to the Lsh region of mouse chromosome 1, which confers resistance in mice to several intracellular parasites.
Restriction fragment length polymorphisms (RFLPs) were observed in BamHI-digested mouse DNA probed with a cDNA for human fibronectin. Analysis of the inheritance of fibronectin RFLPs in AKXD and SWXJ recombinant inbred strains of mice mapped the locus, Fn-1, to the midregion of mouse chromosome 1 about 4 cM distal from the loci encoding gamma-crystallins (Cryg). Loci homologous to genes in the centromeric third of mouse chromosome 1 are also syntenic in rats, humans, and cattle and may, therefore, mark a large conserved chromosomal segment of the mammalian genome.
Restriction fragment polymorphisms were used to order the alpha A-crystallin locus (Crya-1) relative to other genes in mouse t-chromatin and to investigate the relatedness of alpha-A-crystallin sequences among different t-haplotypes. Analysis of DNA from t-recombinant mice mapped Crya-1 to the K end of the H-2 complex and within the distal inverted region characteristic of t-haplotypes. Hybridization with Crya-1 cDNA revealed three distinct phenotypic groups among the 17 different t-haplotypes studied. A majority (9 of 17) of the t-haplotypes were classified into a novel group (Crya-1t) characterized by restriction fragments apparently unique to t-chromosomes and therefore thought to contain alpha A-crystallin sequences descended from the original t-chromosome. A second group of t-haplotypes had restriction fragment patterns indistinguishable from those observed among many common inbred strains of mice of the Crya-1a type, and a third restriction fragment pattern, observed only in the tw121 haplotype, was indistinguishable from the fragment pattern for C3H/DiSn (Crya-1b) and several other inbred strains of mice. Thus, with respect to sequences around the Crya-1 locus, different t-haplotypes show restriction fragment polymorphisms, some of which are comparable to those found in wild-type chromosomes and provide further evidence for genetic heterogeneity in DNA from the distal region of t-haplotypes.
The offspring of DBA/2J male mice exposed to ethylene oxide (EtO) by inhalation had an increased incidence of both dominant visible and electrophoretically detected mutations over that found in control populations. The progeny at risk were obtained from matings during the exposure period and were the products of germ cells that were exposed throughout the entire spermatogenic process. The results reported here suggest that male germ cells repeatedly exposed to EtO during spermatogenesis are susceptible to EtO-induced transmissible damage.
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Somatic cell hybrids, recombinant inbred (RI) mouse strains, and backcross breeding experiments were used to locate the gene of transcobalamin II (Tcn-2), the vitamin B12 binding protein in mouse serum. TCN-2 was found to be useful genetic marker in the somatic cell hybrids. Selected hybrid clones were derived from fusions between GR mouse cells and the Chinese hamster cell line E36. Analysis of mouse specific chromosomal enzyme markers in relationship to TCN-2 secretion, in the hybrid clones, provided provisional evidence for assignment of the Tcn-2 locus to chromosome 11. The strain distribution pattern of the TCN-2 variants S and F in the RI series CXS, constructed from the cross of BALB/cHeA (TCN-2S) with STS/A (TCN-2F), implied a close linkage with the hemoglobin alpha-chain locus (Hba) on chromosome 11. Backcross breeding using inbred strains confirmed these findings and located the Tcn-2 gene closest to the centromere, linked with waved 2 (wa-2) and Hba with recombination frequencies of 6.9 and 19.2% each. The linkage group Tcn-2/wa-2/Hba was established.
Two electrophoretic polymorphisms affecting lens crystallins, designated LEN-1 and LEN-2, have been discovered among inbred strains of mice. Analysis by isoelectric focusing demonstrated that both crystallins are monomeric proteins with isoelectric points at or above pH 7. Both proteins eluted in the low molecular weight (LM) fraction upon Sephadex G-200 gel filtration but LEN-2 was shown to be larger than LEN-1 by G75SF gel filtration and denaturing gel electrophoresis. Linkage analysis demonstrated that the genes encoding LEN-1 and LEN-2 assort independently. Amino acid analysis of the allelic products of the two genes revealed that genetic variants of each respective crystallin were very similar in amino acid compositions but that LEN-1 and LEN-2 were dissimilar crystallins.
Analysis of rat lens soluble proteins by analytical isoelectric focusing detected two inherited electrophoretic differences in low molecular weight (LM) crystallins from inbred strains of rats (Rattus norvegicus). The polymorphic lens crystallins were shown to be similar to a genetically variant LM crystallin, LEN-1, previously described in mice (Mus musculus) and encoded on chromosome 1, at a locus linked to Pep-3 (dipeptidase). Linkage analysis demonstrated that the rat crystallin locus was loosely linked to Pep-3 at a recombination distance of 38 +/- 4.5 U. These data suggest the conservation of a large chromosomal region during the evolution of Rodentia and support the hypothesis that the gamma-crystallins are evolving more rapidly than alpha- or beta-crystallins.
A mouse with a variant hemoglobin was discovered during electrophoretic screening of (C57BL/6J X DBA/2J)F1 progeny of females treated with ethylnitrosourea. The variant trait was transmitted as a simple Mendelian alternate at the Hbb locus in all crosses except those involving the original carrier of the mutation. The proband mouse which received the mutation directly from the mutagen-treated parent was a germinal mosaic for the mutant and normal Hbbs alleles. The mutant allele was designated Hbbs2. The mutant haplotype specifies both an electrophoretically fast hemoglobin band and a hemoglobin band in the normal beta single hemoglobin position. Thus, the mutation has altered one of the tandemly duplicated genes at the Hbbs locus. A comparison of the relative concentrations of the two hemoglobins in Hbbs2 mice demonstrates preferential expression of the mutant gene, possibly analogous to the enhanced expression of Hbbdmaj in the Hbbd haplotype. Analysis of the amino acid sequence of the variant beta-globin revealed that the valine at position 60 was changed to glutamic acid. The simplest mutation mechanism for such an alteration is an A X T----T X A transversion.
We have used a complementary DNA (cDNA) for mouse alpha A-crystallin to probe genomic DNA for restriction fragment length polymorphisms which could be used to map the alpha A-crystallin gene locus (Acry-1) in the mouse genome. Ten of 12 restriction endonucleases produced fragment polymorphism among various inbred strains of mice. A comprehensive strain survey conducted with six endonucleases resulted in the discovery of six allelic forms of Acry-1. Linkage analysis was conducted on DNA from three sets of recombinant inbred strains of mice and demonstrated close linkage of Acry-1 with the major histocompatibility complex (H-2) on chromosome 17. Analysis of congenic and recombinant congenic strains of mice confirmed the linkage of Acry-1 and H-2 and located the alpha A gene to the region between glyoxylase (Glo-1) and H-2K.