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

The efficiency of DNA-mediated transfer of the gene (hprt) for hypoxanthine phosphoribosyltransferase (HPRT; IMP: pyrophosphate phosphoribosyltransferase, EC 2.4.2.8) is dependent upon the recipient cell used. hprt has been transferred into mouse TG8 or Chinese hamster CHTG49 cells at a high frequency, similar to the frequency of the gene (tk) for thymidine kinase (TK; ATP:thymidine 5'-phosphotransferase, EC 2.7.1.21) transfer into mouse LMTK- cells (i.e., 10(-6)). In contrast, the frequency of transfer of hprt into mouse A9 cells was about two orders of magnitude less. The identification of efficient recipient cells for hprt transfer permits the use of DNA-mediated transfer as a bioassay for the gene. Cotransfer of the linked tk gene and the gene (galk) for galactokinase (ATP: D-galactose 1-phosphotransferase, EC 2.7.1.6) to LMTK- cells has been detected once among 87 tk transferrents. This suggests that the distance between the tk and galk genes in the Chinese hamster genome may be smaller than was previously thought. Significant differences between chromosome-mediated and DNA-mediated gene transfer were observed with respect to both the size of the transferred functional genetic fragment and the recipient cell specificity.
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PMID:Cotransfer of linked eukaryotic genes and efficient transfer of hypoxanthine phosphoribosyltransferase by DNA-mediated gene transfer. 692 11

In L5178Y mouse lymphoblasts, ionizing radiation-induced mutant frequencies were dramatically higher when the genetic marker analyzed was heterozygous (tk+/tk-) than when hemizygous (tk+/tk0 or hprt+/hprt0). In contrast, base-change mutagens induced similar mutant frequencies at heterozygous and hemizygous loci. These results indicate that the majority of radiation-induced mutants harbor multilocus lesions, and that these mutants are poorly recovered when the target gene is in a hemizygous chromosomal region. Dose-rate dependence of radiation-induced mutant frequency was demonstrated at the heterozygous tk locus but not at the hemizygous hprt locus; in a cell line deficient in the rejoining of DNA double-strand breaks (DSBs), no dose-rate dependence was observed for either locus. The majority of TK-/- mutants, whether spontaneous or induced by X, alpha-particle or UV radiation, or by photosensitization, showed loss of the entire active tk allele. The percentage of TK-/- mutants exhibiting inactivation of galactokinase, encoded by the neighboring gk gene, was high in UV repair-deficient cells exposed to UV radiation and in DNA DSB repair-deficient lines exposed to X radiation. Thus the presence of unrepaired DNA lesions, whether DSBs or pyrimidine dimers, appears to result in an increase in the percentage of mutants harboring multilocus lesions.
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PMID:Failla Memorial Lecture. The prevalence of multilocus lesions in radiation-induced mutants. 813 37