Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.2.8 (hypoxanthine-guanine phosphoribosyltransferase)
 2,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The segregation of the chick-specific HPRT gene was studied in three Chinese hamster-chick red blood cell hybrid lines. The three lines showed individual segregation kinetics, the segregation taking place in an exponential-like fashion. Bromodeoxyuridine becomes incorporated into the nuclear DNA and increases the spontaneous segregation rate.
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PMID:The effect of bromodeoxyuridine on the segregation of the chicken-specific HPRT gene from Chinese hamster-chick red blood cell somatic hybrids. 29 50

The pattern of segregation of hypoxanthine phosphoribosyltransferase (HPRT, E.C. 2.4.2.8) was determined in synchronized Chinese hamster-chick red blood cell hybrids. Three hybrid lines were synchronized at the G1-S boundary. Bromodeoxyuridine pulses were subsequently applied throughout the S phase, and the frequency of the segregant clones was determined. It was found that the segregation of the chicken-specific HPRT phenotype associated with the loss of a chromosome was potentiated by bromodeoxyuridine administered during the first hour following release of the block.
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PMID:Pattern of segregation of chicken HPRT phenotype in Chinese hamster-chick red blood cell hybrids. 47 10

Cells of the human lymphoblast line WI-L2 and its derivative TK-6 were synchronized by centrifugal elutriation and cell-cycle dependent mutation to 6TGR (HPRT) and OUAR (Na+, K+ ATPase) measured. Bromodeoxyuridine induced 6TGR and OUAR mutations within S phase while butylmethyl-sulfonate induced mutation displayed no cell-cycle dependence. The data indicate that centrifugal elutriation is a facile means to obtain a useful degree of synchrony for these cell lines.
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PMID:Cell-cycle dependent mutation of human lymphoblasts: bromodeoxyuridine and butyl methanesulfonate. 165 42

The L1 gene of human papillomavirus type 16 (HPV-16) driven by the vaccinia virus major late 4b gene promoter has been inserted into three different sites of the vaccinia virus genome. Insertion into the thymidine kinase (TK) gene was achieved by selection of TK- mutants in BUdR on TK- cells. Insertion into two vaccinia virus serine protease inhibitor (serpin) genes was achieved by co-insertion of the Escherichia coli xanthine guanine phosphoribosyltransferase gene linked to the vaccinia virus 7.5K promoter and selection of mycophenolic acid-resistant recombinant viruses. Each recombinant virus expressed a 57K L1 protein at similar levels and with similar kinetics. However, immunization of mice with these recombinant viruses induced different levels of antibody to the L1 protein. Viruses lacking serpin genes B13R and B24R induced significantly higher antibody levels than did viruses lacking the TK gene. The presence of functional B13R and B24R gene products is therefore somehow immunosuppressive at least for antibody responses to the L1 protein of HPV-16.
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PMID:Increased antibody responses to human papillomavirus type 16 L1 protein expressed by recombinant vaccinia virus lacking serine protease inhibitor genes. 217 May 78

It has only recently been possible to demonstrate the expected mutagenic effect of 5-bromodeoxyuridine (BUdR) in heteroploid hamster cells in culture. We have now extended this observation to diploid human fibroblasts utilizing techniques adapted from the work of Albertini and DeMars on X-ray mutagenesis at the hypoxanthine-guanine phosphoribosyltransferase (HGPRT) locus in these cells. In four separate experiments, fibroblasts from a female donor were exposed to 500 micrograms/ml ethylmethane sulfonate (EMS) or 3 micrograms/ml BUdR yielding survivals of 9% and 5%, respectively. After a 6-day expression period, survivors were plated in selection medium containing 0.3 micrograms/ml 8-azaguanine (8-AG). After 3-5 weeks, azaguanine-resistant colonies were isolated for characterization or stained for counting. The average spontaneous mutation rate/cell/generation was 0.6.10(-6). The average induced mutation rates for EMS and BUdR were 7.8.10(-6) and 6.3.10(-6)/cell/generation, respectively. Similar results were obtained in two experiments with an additional fibroblast line. Mutant colonies isolated following BUdR treatment demonstrated from 1.4 to 61.5% of the HGPRT activity of the parental line and showed at least 8% Barr bodies, excluding the possibility of contamination by Lesch-Nyhan cells. This demonstration of a BUdR effect comparable to that of an alkylating agent or X-irradiation opens the study of mutation due to base-analog substitution in diploid human cells.
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PMID:Mutagenic effect of BUdR in diploid human fibroblasts. 453 17

We constructed a subgenomic cosmid library of DNA replicated early in the S phase of normal human diploid fibroblasts. Cells were synchronized by release from confluence arrest and incubation in the presence of aphidicolin. Bromodeoxyuridine (BrdUrd) was added to aphidicolin-containing medium to label DNA replicated as cells entered S phase. Nuclear DNA was partially digested with Sau 3AI, and hybrid density DNA was separated in CsCl gradients. The purified early-replicating DNA was cloned into sCos1 cosmid vector. Clones were transferred individually into the wells of 96 microtiter plates (9,216 potential clones). Vigorous bacterial growth was detected in 8,742 of those wells. High-density colony hybridization filters (1, 536 clones/filter) were prepared from a set of replicas of the original plates. Bacteria remaining in the wells of replica plates were combined, mixed with freezing medium, and stored at -80 degrees C. These pooled stocks were analyzed by polymerase chain reaction to determine the presence of specific sequences in the library. Hybridization of high-density filters was used to identify the clones of interest, which were retrieved from the frozen cultures in the 96-well plates. In testing the library for the presence of 14 known early-replicating genes, we found sequences at or near 5 of them: APRT, beta-actin, beta-tubulin, c-myc, and HPRT. This library is a valuable resource for the isolation and analysis of certain DNA sequences replicated at the beginning of S phase, including potential origins of bidirectional replication.
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PMID:Construction of a cosmid library of DNA replicated early in the S phase of normal human fibroblasts. 1086 48