Hypoxanthine phosphoribosyltransferase hprt

Miller AD, Jolly DJ, Friedmann T, Verma IM. 1983. A transmissible retrovirus expressing human hypoxanthine phosphoribosyltransferase (HPRT) Gene transfer into cells obtained from human deficient in HPRT. Proc Nat Acad Sci USA. 80 4709-4713. 

W.M. (2003) Mutations induced by (-)-anti-llR,12S-dihydrodiol 13 S,1477-epoxide of dibenzo[a,7]pyrene in the coding region of the hypoxanthine phosphoribosyltransferase (Hprt) gene in Chinese hamster V79 cells. Environ. Mol. Mutagen., 41, 131-139. 

Since a recombination event between two loxP sites some distance apart or positioned on different chromosomes, is relatively rare, presumably because of physical constraints, a reflection of chromosome architecture and decreased proximity, such strategies are designed incorporating a binary positive selection system that is only activated after a successful recombination recreates the cassette. Thus, the desired recombination event will reconstruct the selectable genetic marker, from two silent portions placed adjacent to each of the loxP sites. The most commonly used selection systems include the reconstitution of a human hypoxanthine phosphoribosyltransferase (HPRT) minigene (16-20), or the juxtaposition of a strong promoter upstream of a selectable marker. 

Puig, J. G., Torres, R. J., Mateos, E A. et al. The spectrum of hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency. Clinical experience based on 22 patients from 18 Spanish families. Medicine (Baltimore) 80 102-112,2001. 

HPRT hypoxanthine phosphoribosyltransferase acidosis, and stroke-like episodes... 

Purines that result from the normal turnover of cellular nucleic acids can be reconverted into nucleoside triphosphates and used by the body. Thus, they are "salvaged" instead of being degraded to uric acid. PRPP is the source of the ribose-phosphate, and the reactions are catalyzed by adenine phosphoribosyltransferase, and hypoxanthine-guanine phosphoribosyltransferase (HPRT). 

D.G. Sculley, P.A. Dawson, B.T. Emerson, andR.B. Gordon. 1992. A review of the molecular basis of hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency Hum. Genet. 90 195-207. (PubMed)... 

Azaguanine brought about a 60% increase in the lifespan of mice with leukemia L1210. However, its ribonucleoside was inactive because it did not become phosphorylated, whereas 8-azaguanine was transformed by HPRT (hypoxanthine phosphoribosyltransferase) into its nucleotide, which RNA can incorporate." On the other hand, 8-azaadenosine" and 8-azainosine (9-ribofuranosyl-8-azahypoxanthine)," " both of which dis-... 

Figure 43-2 Simplified scheme of the metabolism of azathioprine and 6-mercaptopuHne to 6-thioguanine nucleotides (TGNs). TPMXThiopurine S-methyitransferase XO, xanthine oxidase HPRT hypoxanthine phosphoribosyltransferase. (Redrawn from Clunie GP, Lennard L Relevance of thiopunne methyltransferase status in rheumatology patients receiving azathioprine. Rheumatology (Oxford) 2004 43 13-8. Reproduced by permission from Oxford University Press.)...

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