Hepatotoxicity associated with piroxicam use.
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Biomedical subjects
Publications and source records attributed to C Jones.
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The determination of the physical map of human chromosome 11 will require more clones than are currently available. We have isolated an additional 1001 new markers in a bacteriophage vector from a somatic cell hybrid cell line that contains most of chromosome 11, except the middle of the short arm. These markers were localized to five different regions, 11p15-pter, 11p12-cen, 11q11-q14, 11q14-q23, and 11q23-qter, by a panel of previously characterized somatic cell hybrids. The region 11q11-14 harbors genes that have been shown to be important in breast cancer, B-cell lymphomas, centrocytic lymphomas, asthma, and multiple endocrine neoplasia, type 1 (MEN1). To determine the positions of the recombinant clones located there, we developed a new series of radiation-reduced somatic cell hybrids. These hybrids, together with those previously characterized, allowed us to map the 11q11-q14 markers into 11 separate segregation groups.
Constitutional and somatic chromosomal abnormalities of the chromosome 11p15 region are involved in an overgrowth malformation syndrome, the Beckwith-Wiedemann syndrome (BWS), and in several types of associated tumors. The bias in parental origin for the different etiologic forms of this syndrome and for loss of heterozygosity in the tumors suggests that a gene (or genes) mapping to this region undergoes genomic imprinting. However, the precise localization of the locus (or loci) for the BWS and associated tumors is still unknown and more markers are required. We therefore isolated 11p15 markers from two libraries: the first one obtained by microdissection of the chromosome 11p15.5 region and the second one, a phage library, constructed from a hybrid cell line containing this region as its sole human DNA. Of 19 microclones isolated from the microdissection library, 11 were evolutionarily conserved. Four phage clones were isolated; one (D11S774) detected a highly informative variable number of tandem repeats (VNTR) and another (D11S773) a biallelic polymorphism. These clones were sublocalized using a panel of somatic cell hybrids that defines eight physical intervals in 11p15.5. Twenty-one clones map to the distal interval that harbors the BWS locus.
Fifty-four clones containing human inserts were selected from a cosmid library constructed from a somatic cell hybrid containing chromosome 11p15.3-p15.5 as its only human complement. In 32 of these clones, 63 polymorphic systems were identified with a panel of restriction enzymes: 57 conventional RFLP systems and 6 highly polymorphic VNTR systems. Although we examined the cosmid with only seven enzymes, 18 clones (including 6 VNTRs) were polymorphic with three or more enzymes. The results suggested that DNA sequences on the peritelomeric region of chromosome 11p tend to be highly variable. Because these markers are highly informative, they will be excellent resources for investigations of hereditary diseases and tumor suppressor genes in this region of chromosome 11.
Myotonic dystrophy (DM) is caused by a defect in an unknown gene that maps to 19q13.3, flanked by the tightly linked markers ERCC1 on the proximal side and D19S51 on the distal side. We report the isolation and characterization of overlapping YAC and cosmid clones around D19S51 for the construction of a physical map around this locus. The resulting contig contains the markers D19S51 and D19S62 (another new marker tightly linked to the DM locus) and the distal breakpoint of a radiation hybrid cell line used in the physical mapping of the DM region. We have compared the restriction maps of the YACs and cosmids with that of the genome to investigate the fidelity of these clones.
We have characterized a panel of somatic cell hybrid cell lines which contain different portions of human chromosome 10. Genomic DNA from the somatic cell hybrids was tested for hybridization with each of an ordered set of probes used previously to construct a genetic map of chromosome 10, as well as several additional probes, previously localized by in situ hybridization. Hybridization of an unmapped probe to the cell line DNAs can be used to determine its most likely position on the chromosome relative to the mapped set of probes. Genomic DNA from two of the cell lines has been used to construct region-specific cosmid and bacteriophage libraries, and clones derived from these libraries were localized by hybridization to the panel of hybrid cell lines. Several of these probes reveal restriction fragment length polymorphisms which have been genetically mapped. Three of the probes map near the locus for multiple endocrine neoplasia type 2A, and one of these probes, BG-JC353 (D10S167), maps between RBP3 and TB14.34 (D10S34). Another probe, CRI-J282 (D10S104), is close to the FNRB locus. The panel of hybrid cell lines is thus useful for rapidly localizing unmapped probes and as a source of DNA for the construction of recombinant libraries derived from specific regions of the chromosome.
Milk proteins are crucial for the development of all newborn mammals. Caseins that constitute the bulk of the protein in mammalian milk have been shown to be members of a multigene family in at least two species. They are among the most rapidly diverging groups of proteins, and their numbers vary widely among species. beta- and kappa-Caseins are the only caseins present in human milk. Using polymerase chain reaction on genomic DNA from somatic cell hybrids, we have localized the human beta-casein gene (CSN2) to 4pter----q21.
Thirty-one new RFLP systems corresponding to 24 loci have been identified from a chromosome 10-specific cosmid library. Twelve of the markers on the proximal long arm (cen-q11.2) of this chromosome, including four RFLP systems for the RET locus, will be especially useful in efforts to identify the gene responsible for multiple endocrine neoplasia type 2A (MEN2A). The new panel of markers also may contribute to fine-scale mapping of tumor suppressor genes associated with glioblastoma multiforme or renal cell carcinoma, because allelic deletions in these tumors have implied the presence of a tumor suppressor gene(s) on chromosome 10.
Diverse strains of Helicobacter pylori were examined in order to initiate a molecular epidemiological typing scheme for this agent of human gastritis. Twelve differently-sized plasmids from 1.8 to 63 kbp were identified in those strains harbouring extrachromosomal DNA. Recombinant DNA probes were cloned randomly from the chromosome of the (plasmid-free) type strain (NCTC 11637), and used to probe genomic Southern blots for restriction site variation in and around homologous loci. Genus-specific probe DNAs were obtained which grouped strains on the bases of DNA base substitution or rearrangements. On the basis of the four probes examined, all strains exhibited intraspecific chromosomal divergence, indicating that H. pylori is highly diverse genetically, but nonetheless susceptible to chromosome and plasmid molecular typing.
Human papilloma virus type 16 (HPV-16) and herpes simplex virus type 2 (HSV-2) are human viruses implicated in the development of cancer, in particular cervical cancer. The ability of HSV-2 and HPV-16 to transform early passage human cells was examined in this report. For these studies, gingival fibroblasts were utilized. One gingival cell strain was derived from a normal individual (N-16). The second cell strain was derived from hyperplastic gingival tissue of an epileptic individual (R-30) treated with phenytoin, an antiseizure drug. A common side effect of phenytoin is the induction of gingival overgrowth. R-30 cells contained a stable chromosomal translocation between chromosomes 8 and 18 and expressed higher steady state levels of c-myc. HPV-16 DNA efficiently immortalized R-30 cells but not N-16 cells. R-30 cells cotransfected with HPV-16, and HSV-2 viral DNAs were more aneuploid than R-30 cells transfected with HPV-16 DNA alone. Additionally, R-30 cells cotransfected with both viral DNAs grew better in soft agar than R-30 cells transfected with HPV-16 DNA alone. HSV-2 DNA was detected in transformed cells by polymerase chain reaction. These results suggested R-30 cells were immortalized more efficiently by HPV-16 and further imply that HPV-16 and HSV-2 DNA fragments can cooperate during multistep transformation.
In order to provide a profile of the plasmid gene pool in Salmonella prior to the clinical use of antibiotics, a molecular genetic analysis was made of plasmids in strains collected by E.D.G. Murray between 1917 and 1954. These pre-antibiotic era (PAE) salmonellae contain conjugative plasmids of the same incompatibility groups as contemporary enterobacterial plasmids. Upon analysis of total plasmid content, 42 plasmids, sized between 23 and 72 MDa, were found. We defined and investigated six groups of these PAE Salmonella plasmids in terms of three groups of genes; those involved in plasmid maintenance and incompatibility, DNA repair and virulence. Of the five groups, three were replicon-typed to groups IncI1, IncX and IncFII; one group exhibited no homology to contemporary Inc/Rep probes, and one group represented virulence plasmids containing a common plasmid-partitioning locus. The results indicated that most of the PAE groups were progenitors of contemporary R-plasmids, except for the virulence plasmids, which have generally not evolved as vectors of antibiotic resistance.
In Salmonella heidelberg the copy number of the Salmonella-specific insertion element IS200 was found to vary from four to six. All strains tested contained at least one common insertion site which was serovar specific, and most strains contained three common sites. Concurrent analysis of plasmids indicated that all insertion sequence copies were chromosomally located, and also supported the equivalence of an IS200 fingerprint and clonality. Seven intra-serovar clonal lines were thereby identified. One of these was associated with human infections, including septicaemias. Another was associated with chicken as a host: all these strains also carried a unique plasmid of 23 MDa, which was typed as a member of the IncX group. The chromosomal fingerprint of a third clone showed it to be a descendant of the chicken line marked by a single IS200 transposition. One or two representatives of four other clonal lines were identified. These lines of S. heidelberg could be related by divergent evolution, and the most recent relatives conformed to a continuous branching process model of IS200 transposition. This insertion sequence provided a highly discriminatory molecular marker of the S. heidelberg chromosome, and two of the seven clonal lines so identified were associated with distinct clinical/epidemiological contexts.
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The sexually dimorphic expression of the urinary protein genes of mice (Mup genes) in the liver is mediated by the different male and female temporal patterns of circulating GH. Normal females were induced to male levels when GH was administered by injection to mimic the male GH pattern, showing that expression at the male level does not require a male sex steroid status in addition to intermittent GH. Two Mup-alpha 2u-globulin hybrid transgenes with different Mup gene promoters showed sexually dimorphic expression, and their expression in females increased to male levels upon testosterone treatment. GH-deficient (lit/lit) mice did not express these transgenes, and GH-deficient females did not respond to testosterone treatment, showing that GH was required for induction. Both normal and GH-deficient females were induced to male levels when GH was administered by injection. This is the first report of a transgene responsive to GH. A transgene consisting of a Mup promoter fused to a Herpes simplex virus thymidine kinase reporter sequence also showed sexual dimorphism, although to a lesser degree. It was expressed at the same level in normal females and GH-deficient mice of both sexes and was induced when GH-deficient mice were treated with GH. We propose that this transgene has a basal constitutive expression, possibly due to the absence of any rodent DNA downstream of the promoter. Since expression of the transgene was significantly induced by GH, the GH response is due at least in part to sequences in the promoter region.
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We have extended our mapping effort on human chromosome 11 to encompass a total of 262 DNA markers, which have been mapped into 24 intervals on chromosome 11; 123 of the markers reveal RFLPs. These clones are scattered throughout the chromosome, although some clustering occurs in R-positive bands (p15.1, p11.2, q13, and q23.3). Fifty-two of the markers were found to contain DNA sequences conserved in Chinese hamster, and some of these 52 also cross-hybridized with DNA from other mammals and/or chicken. As the length of chromosome 11 is estimated at nearly 130 cM, the average distance between RFLP markers is roughly 1 cM. The large panel of DNA markers on our map should contribute to investigations of hereditary diseases on this chromosome, and it will also provide reagents for constructing either fine-scale linkage and physical maps or contig maps of cosmids or yeast artificial chromosomes.
Familial multiple endocrine neoplasia type 1 (MEN 1) is an autosomal dominant disorder characterized by the combined occurrence of tumors of the parathyroid glands, the endocrine pancreas, and the pituitary gland. MEN 1 tumors have previously been shown to be associated with the loss of alleles on chromosome 11, and deletion mapping studies together with family linkage studies have localized the MEN 1 gene to 11q13. A detailed genetic map around the MEN 1 locus is required to facilitate further characterization and cloning of the gene (MEN1). We have characterized a panel of seven rodent-human somatic cell hybrids which contain fragments of human chromosome 11 with breakpoints in the pericentromeric region by using eight DNA sequences (D11S149, PGA, PYGM, D11S97, INT2, D11S37, D11S533, and D11S147) to define the region containing MEN1. This will facilitate the rapid localization of additional DNA sequences in this region. In addition, we have used a highly polymorphic repetitive degenerate hexanucleotide sequence, designated D11S533, for segregation studies in one family with MEN 1. These molecular genetic approaches will help to define a precise 1 to 2 centiMorgan map around MEN1.