We describe a method for isolating cosmid clones randomly from mouse chromosome 17. A cosmid library was constructed from the mouse-Chinese hamster cell line R4 4-1 that contains a limited amount of mouse DNA (chromosomes 17 and 18 and some other unidentified material) on a Chinese hamster background. The library was screened with the murine repetitive sequence probe pMBA14, which selectively hybridizes with mouse DNA. The mouse-derived cosmid clones thus identified were individually hybridized with DNA from the mouse-Syrian hamster cell line JS17 containing all mouse chromosomes except chromosome 17 on a Syrian hamster background. We deduced that the cosmid clones that contained sequences absent in JS17 were derived from mouse chromosome 17. One of the chromosome 17-derived cosmid clones, 3-4-1 (located proximal to the T122/T66C segment) was found to be highly polymorphic among European wild-mouse populations and may be a useful probe to elucidate the evolution and migration of Mus species. The randomly isolated mouse-derived cosmid clones can also be screened for the presence of functional genes. Using testicular cDNA as a probe, a testis-specific gene was cloned from mouse chromosome 17.

Animals↗

PubMed1987

Major histocompatibility complex gene organization in the mole rat Spalax ehrenbergi: evidence for transfer of function between class II genes.

A genomic DNA library prepared from the kidney of the mole rat Spalax ehrenbergi was screened with mouse probes representing major histocompatibility complex genes that encode alpha and beta polypeptide chains of class II molecules (alpha and beta genes). Restriction maps were constructed for the cross-hybridizing clones, and the class II genes borne by these clones were identified. By this procedure, five main regions containing class II genes were established. One region contained four genes and two gene fragments, the second region contained two genes, the third region contained one gene and one gene fragment, and the remaining two regions contained one gene each. Altogether, six beta genes, two alpha genes, and three alpha-gene fragments were identified. Two of the genes (one alpha and one beta) were established as belonging to the DQ subclass, and all other genes were found to be members of the DP subclass. (Subclass designations are based on the human HLA class II genes). No genes belonging to the DR and DO (DZ) subclasses were found in the library. The absence of DR genes in S. ehrenbergi was also indicated when other experimental methods were used. At least some of the DP loci are polymorphic and most likely also functional. Thus, in the evolution of the mole rat, the DR (and probably also the DO) loci have been deleted and their function(s) has been taken over by the DP loci, which have expanded to a great extent. These findings argue for functional interchangeability of the individual subclasses of class II loci.

Animals↗

PubMed1987

Polymorphism of unique noncoding DNA sequences in wild and laboratory mice.

Two DNA probes, D17Tu1 and D17Tu2, were isolated from a genomic DNA library containing only two mouse chromosomes, one of which is chromosome 17, carrying the major histocompatibility complex (H-2), as well as the t complex genes. The D17Tu1 probe was mapped to the centromeric region of chromosome 17 and the D17Tu2 probe to the S region of the H-2 complex. Neither of the two probes appeared to detect any genes, but both contained unique, nonrepetitive sequences. Typing of DNA obtained from a large panel of mice revealed the presence of four D17Tu1 patterns in inbred mouse strains, one very common, one less common, and two present in one strain each. The two common patterns could not be detected in appreciable frequencies in the European wild mice tested (one of the two patterns was, however, found in Australian wild mice). Conversely, the patterns found frequently in European wild mice are absent in the laboratory mice. We therefore conclude that wild mice from the sampled regions of Europe could not have provided the ancestral stocks from which inbred strains were derived. Only one D17Tu1 pattern was found in all the populations of Mus musculus tested, while eight patterns were found in Mus domesticus, with virtually all the populations being polymorphic. We suggest that this difference reflects different modes in which the two species colonized Europe. The distribution of the D17Tu2 patterns in inbred strains correlates with the distribution of H-2 haplotypes.

Animals↗

PubMed1987

Evolutionary diversification of class II P loci in the Mhc of the mole-rat Spalax ehrenbergi.

The class II region of the major histocompatibility complex (Smh) in the mole rat, Spalax ehrenbergi, consists of only two gene families, P and Q, instead of the four families (P, O, Q, and R) found in all other mammals studied to date. The Spalax P family consists of at least four beta and three alpha genes or gene fragments. In DNA-hybridization experiments, two of the beta genes behave as bona fide P-family members in that they hybridize strongly with human DP beta probes and hybridize weakly with probes specific for other class II gene families. The other two beta genes, on the other hand, hybridize weakly with human DP beta probes and nearly as well with human DQ beta probes. To determine the evolutionary relationships among these P-like genes, we have sequenced one of them. The sequence reveals, on the basis of its organization, that the gene clearly belongs to the P family, yet, on the basis of its nucleotide sequence, it is only slightly more similar to human DP than to human DQ genes. These results indicate that in the Spalax the P family of genes split into two subfamilies, PA and PB. For unknown reasons, one of these subfamilies (PB) retained more similarity to the Q gene family than did the other (PA).

Amino Acid Sequence↗

PubMed1987

Evolutionary expansion of Mhc class I loci in the mole-rat, Spalax ehrenbergi.

A cosmid genomic library was prepared from a single individual of the rodent Spalax ehrenbergi, the mole rat, captured in Israel. The library was screened with a mouse probe hybridizing with all mouse class I major-histocompatibility-complex (Mhc) genes; the cross-hybridizing clones were isolated; and their restriction maps were prepared using five enzymes. A total of 93 class I-bearing clones could be identified in the library. Forty-five of these clones showed partial overlaps and could be arranged into 14 clusters. Eleven of these clusters could be shown to contain two class I genes each; the remaining clusters, as well as most of the non-overlapping clones, each contained one class I gene. After the elimination of clones with possible cloning artifacts and of clones that may carry allelic forms of a given gene in the heterozygous animal, the total number of class I loci identified in Spalax is approximately 65. The high number of loci probably arose from the duplication of either the entire class I set or the different class I families. The high number of gene copies might represent a means of selecting different functional genes from the family in different mammalian orders. Three of the approximately 65 Spalax class I genes cross-hybridize with a probe specific for the mouse K, D, and L genes; two of these genes are in the same cluster. These three elements might possibly be the functional class I genes of the mole rat.

Animals↗

PubMed1987

The major histocompatibility complex and the Fugu aspect of immunity.

Explore the source record for details and available documents.

Animals↗

PubMed1987

Evidence of digoxin metabolism by the kidney.

By performing single pass experiments in the dog, we could identify by thin layer chromatography a digoxin metabolite produced by the kidney. In vitro studies verify that this new species is produced by the brush border membrane of the renal tubular cell.

Animals↗

PubMed1987