Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00492 (hypoxanthine-guanine phosphoribosyltransferase)
 2,385 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mouse teratocarcinoma cells from the OTT6050 ascites tumor were established in tissue culture and selected for 5-bromodeoxyuridine (BrdUrd) resistance. The embryonal carcinoma cells grew without a feeder layer, remained deficient for thymidine kinase (EC 2.7.1.75), and differentiated like the original tumor into various tissues after subcutaneous injection into 129 mice. We fused the BrdUrd-resistant mouse teratocarcinoma cells with HT1080-6TG human diploid fibrosarcoma cells deficient in hypoxanthine phosphoribosyltransferase (EC 2.4.2.8) and selected for hybrid cells in hypoxanthine/aminopterin/thymidine medium. The resulting hybrid cells segregated human chromosomes quickly and retained one to three human chromosomes including chromosome 17 that carries the human genes for thymidine kinase and galactokinase (EC 2.7.1.6). Single hybrid cells from five independent clones containing human chromosome 17 were injected into mouse blastocysts bearing several genetic markers that affect the coat color phenotype and strain-specific enzyme variants in order to detect tissue differentiation derived from the injected cells. After the injection of single hybrid cells into a total of 103 experimental blastocysts that had been surgically transferred to pseudopregnant foster mothers, 49 mice were born and 2 of them clearly revealed coat mosaicism. In 2 of 17 mice thus far analyzed, the injected hybrid cells proved to be capable of participating substantially in development of seven different organs. However, human gene products have not yet been detected unequivocally in those tissues and weak human-specific galactokinase activity could be recovered only from two mosaic tissues. Our results demonstrate that, after in vitro culture and selection, at least some of the human-mouse hybrid cells still retain their in vivo potential to differentiate and become functionally integrated in the living organism. It now seems feasible to cycle mouse teratocarcinoma cells carrying human genetic material through mice via blastocyst injection to study human gene expression during differentiation.
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PMID:Chimeric mice derived from human-mouse hybrid cells. 20 75

Sixty-eight independent hybrid clones were isolated after irradiated normal human lymphocytes were fused with Chinese hamster fibroblasts lacking hypoxanthine-guanine phosphoribosyltransferase activity. The cells were grown under selective conditions requiring retention of the X chromosome-linked locus for human hypoxanthine-guanine phosphoribosyltransferase. The frequency and patterns of cotransference of human phosphoribosylpyrophosphate synthetase with the selected marker and with additional X-linked enzymatic markers confirm X linkage of the structural gene for human phosphoribosylpyrophosphate synthetase and support assignment of this gene to a position on the long arm of the X, between the loci for alpha-galactosidase and hypoxanthine-guanine phosphoribosyltransferase.
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PMID:Regional localization of the gene for human phosphoribosylpyrophosphate synthetase on the X chromosome. 21 84

Thymidine kinase-deficient OTT6050 mouse teratocarcinoma cells were fused with hypoxanthine phosphoribosyltransferase-deficient Fu5AH rat hepatoma cells by means of inactivated Sendai virus. The resulting hybrid cells, which were selected in hypoxanthine/aminopterin/thymidine medium, retained almost all of the mouse chromosomes and various numbers of rat chromosomes, and showed many chromosomal rearrangements. The hybrid cells, as well as both parental lines, formed tumors after subcutaneous injection into athymic nude mice. Single rat--mouse hybrid cells from a clonally established subline were transplanted into C57BL6/J mouse blastocysts carrying many genetic markers suitable for the detection of hybrid cell-derived tissue contributions. From 144 blastocysts, each of which was injected with a hybrid cell and then surgically transferred to the uterus of a pseudopregnant foster mother, 62 adult mice developed without any visible coat mosaicism. However, three of these mice showed internal hybrid-cell participation in their livers and a limited number of organs of endomesodermal origin. A tumor classifiable as hemangio endothelioma was found in the liver, the only mosaic tissue, of one of the chimeric mice. Nine different rat-specific enzyme variants were detected in the mosaic organs. A considerable number of variations concerning the presence and quantitative activity of the foreign gene products probably resulted from chromosomal segregation, tissue-specific gene activity, or dosage compensation during differentiation in vivo. Our results demonstrate that cultured malignant rat--mouse hybrid cells differentiate normally and become functionally integrated during development. The appearacne in vivo of certain rat-specific gene products that are not found in the hybrid cells under conditions in vitro indicates differential gene expression of the introduced xenogeneic chromosomes.
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PMID:Xenogeneic gene expression in chimeric mice derived from rat--mouse hybrid cells. 28 11

An erythromycin-resistant mutant, ERY2301, was isolated from ethidium bromide-treated HeLa cells in the presence of erythromycin at 300 micrograms/ml. ERY2301 cells were enucleated and the anucleate cytoplasts were fused with D98/AH-2, a hypoxanthine phosphoribosyltransferase-deficient variant of HeLa cells. The resultant cybrids were isolated in a double selective medium containing erythromycin and 6-thioguanine. Cybrid formation occurred at a frequency of 10(-3) to 10(-4). In vitro protein synthesis by intact and Triton X-100 treated mitochondria isolated from ERY2301 was resistant to the macrolide antibiotics erythromycin and carbomycin, but was sensitive to chloramphenicol. These results suggest that the site of erythromycin resistance in ERY2301 may be at the level of mitochondrial protein synthesis and indicate that this trait is cytoplasmically inherited and, therefore, presumably encoded in the mitochondrial genome.
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PMID:Cytoplasmic inheritance of erythromycin resistance in human cells. 29 86

The behaviour of human cells arrested in mitosis can be severely perturbed so as to generate numerous small minisegregants containing very few chromosomes. These cells can be separated according to size and DNA content and fused with intact cells. In this paper we describe the production and some properties of proliferating cell hybrids generated by fusion of human minisegregant cells derived from a HeLa strain with mouse A9 cells deficient in hypoxanthine phosphoribosyltransferase (HPRT, EC 2.4.2.8). The hybrids were shown to contain up to 10 human chromosomes including a single X. Independently derived hybrid clones were quantitatively characterized and compared with the parental phenotypes with respect to HPRT. Human isozymes of each of the 3 enzymes HPRT, glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and phosphoglycerate kinase (EC 2,7.2.3) were found. Tests to evaluate both structure and function of HPRT were utilized. The specific activity of HPRT of more than 10 hybrids tested was approximately 10% that of the HeLa parent. Structural characterization of HPRT from hybrid cells as evidenced by heat inactivation and electrophoretic mobility results in a 'human-like' phenotype. Functional characterization of parental HPRT results in kinetic constants for cofactor and substrate which do not permit distinction of human and of human and mouse enzymes; HPRT from the minisegregant hybrids had normal kinetic constants. The reduced specific activity of HPRT in the hybrids is discussed in terms of the inability of the mouse environment to regulate the full expression of the human structural gene.
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PMID:Transfer of human chromosomes via human minisegregant cells into mouse cells and the quantitation of the expression of hypoxanthine phosphoribosyltransferase in the hybrids. 56 87

The availability of systems which permit the selective elimination of marsupial cells from fused cultures is an essential requirement for the production of marsupial X eutherian somatic cell hybrids. Such hybrids have particular advantages for genetic studies of mammalian cells. We describe the isolation and characterization of several drug-resistant marsupial cell strains. We have selected strains resistant to concentrations of 10 micrograms/ml of the purine analogues 8-azaguanine and 6-thioguanine. Several of these strains were found to be deficient in the enzyme hypoxanthine phosphoribosyltransferase and consequently sensitive to hypoxanthine-aminopterin-thymidine (HAT) selective medium. We have also isolated marsupial cell strains resistant to concentrations of 22 micrograms/ml of the thymidine analogue 5-bromodeoxyuridine. These strains were thymidine kinase deficient and HAT sensitive. Drug resistance was a stable characteristic maintained for many generations in the absence of the drug. However, inhibition of growth of these drug-resistant strains was strongly density dependent, a factor that caused difficulties in the selection of hybrids. We have also developed selective systems which exploit differences between marsupial and eutherian cells in sensitivity to growth in ouabain, and in adhesiveness and other growth properties. Marsupial cells were found to be naturally much more sensitive to ouabain than rodent cells, a phenomenon that should be useful in the selection of marsupial X rodent cellular hybrids. We discuss a number of difficulties associated with the derivation and use of variant marsupial cell strains.
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PMID:Fusion and hybridization of marsupial and eutherian cells. V. Development of selective systems. 56 74

Hybridization of mutant cell lines deficient in hypoxanthine-guanine phosphoribosyl transferase (HGPRT; E.C.: 2.4.2.8) from a variety of established rodent sources with HGPRT plus human cells yielded progeny cells which grew in selective medium containing hypoxanthine, aminopterin and thymidine (HAT). The same result was obtained when the human cell used was an HGPRT minus transformed line derived from a patient with the Lesch-Nyhan syndrome. Electrophoretic analysis indicated that all HAT-resistant progeny clones contained an active HGPRT enzyme which was indistinguishable from the wild type enzyme of the corresponding normal rodent cells. In contrast, no HAT-resistant cells have been obtained when the same HGPRT minus rodent cells were subjected to fusion processes in the absence of human cells or when they fused with similarly derived HGPRT minus mutant cells of other rodents. Reversion in expression of the rodent gene for HGPRT was detected in clones which retained one or more human chromosomes and in clones which contained no detectable human chromosomal material. The observed re-expression of rodent HGPRT in HAT-resistant clones suggests that HGPRT plus as well as HGPRT minus human cells contributed a factor which determined the expression of respective rodent structural genes for HGPRT. In contrast, HGPRT minus rodent cells were unable to induce the synthesis or normal HGPRT in the cells derived from the patient with the Lesch-Nyhan syndrome.
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PMID:Reversion in expression of hypoxanthine-guanine phosphoribosyl transferase following cell hybridization. 117 Jan 83

Somatic cell hybridization techniques were applied to gene linkage analysis in the laboratory mouse. Cells of an established line of Chinese hamster lung fibroblasts were fused with mouse embryo fibroblasts and with mouse peritoneal macrophages obtained from different inbred strains. From 3 hybridization experiments, 123 primary and secondary clones were isolated in HAT selective medium and 24 were back-selected in 8-azaguanine. Hybrid clones were characterized for the expression of 16 murine isozymes by starch, acrylamide, and Cellogel electrophoresis, and on the basis of segregation data, 3 syntenic associations could be made. Malate oxidoreductase decarboxylating (MOD) and mannose phosphate isomerase (MPI) segregated concordantly, confirming an established linkage relationship; adenine phosphoribosyltransferase (APRT) segregated concordantly with glutathione reductase (GR) which is known to be on chromosome 8; alpha-galactosidase was observed to be syntenic with hypoxanthine phosphoribosyltransferase (HPRT), and X-linked enzyme. All other isozymes examined segregated independently of one another.
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PMID:Gene linkage analysis in the mouse by somatic cell hybridization: assignment of adenine phosphoribosyltransferase to chromosome 8 and alpha-galactosidase to the X chromosome. 123 12

The abilities to introduce foreign DNA into the genome of mice and to visualize gene expression at the single-cell level underlie a method for defining individual elements of a genetic program. We describe the use of an Escherichia coli lacZ reporter gene fused to the promoter of the gene for hypoxanthine phosphoribosyl transferase that is expressed in all tissues. Most transgenic mice (six of seven) obtained with this construct express the lacZ gene from the hypoxanthine phosphoribosyltransferase promoter. Unexpectedly, however, the expression is temporally and spatially regulated. Each transgenic line is characterized by a specific, highly reproducible pattern of lacZ expression. These results show that, for expression, the integrated construct must be complemented by elements of the genome. These elements exert dominant developmental control on the hypoxanthine phosphoribosyltransferase promoter. The expression patterns in some transgenic mice conform to a typological marker and in others to a subtle combination of typology and topography. These observations define discrete heterogeneities of cell types and of certain structures, particularly in the nervous system and in the mesoderm. This system opens opportunities for developmental studies by providing cellular, molecular, and genetic markers of cell types, cell states, and cells from developmental compartments. Finally this method illustrates that genes transduced or transposed to a different position in the genome acquire different spatiotemporal specificities, a result that has implications for evolution.
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PMID:Patterns of expression of position-dependent integrated transgenes in mouse embryo. 169 27

We have selected mutations in genes encoding components of the signaling pathway for alpha interferon (IFN-alpha) by using a specially constructed cell line. The upstream region of the IFN-regulated human gene 6-16 was fused to the Escherichia coli guanine phosphoribosyltransferase (gpt) gene and transfected into hypoxanthine-guanine phosphoribosyltransferase-negative human cells. These cells express gpt only in the presence of IFN-alpha. They grow in medium containing hypoxanthine, aminopterin, and thymidine plus IFN and are killed by 6-thioguanine plus IFN. Two different types of mutants were obtained after treating the cells with mutagens. A recessive mutant, selected in 6-thioguanine plus IFN, was completely resistant to IFN-alpha but responded normally to IFN-gamma and, unexpectedly, partially to IFN-beta. A constitutive mutant, selected in hypoxanthine-aminopterin-thymidine alone, was abnormal in expressing endogenous genes in the absence of IFN. Both types revert infrequently, allowing selection for complementation of the defects by transfection.
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PMID:Use of a selectable marker regulated by alpha interferon to obtain mutations in the signaling pathway. 251 75


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