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 nuclear matrix is believed to contain sites of assembly of protein complexes that catalyze the initiation of DNA replication as well as DNA elongation. To explore this relationship, DNA replicated by human fibroblasts at the beginning of the S phase was purified and used to construct a cosmid library. Hybridization studies with a subgroup of clones (about one-sixth of the total clones in this library) showed that many of them were highlighted by probes prepared from early replicating DNA, as well as from nuclear matrix-associated DNA. Statistical analysis showed a positive correlation between these hybridization results. We seek to identify origins of replication that are activated early in the S phase of the cell cycle in human cells. Therefore, clones isolated from this library are being analyzed for the presence of structural motifs that have been found in other origins of replication and for potential sites of attachment to the nuclear matrix. This method of analysis is illustrated here using the published sequences for the origins of replication reported for the human lamin B2 and HPRT genes.
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PMID:On the relationship of matrix association and DNA replication. 1081 97

A quantitative PCR method was used to map a functional origin of DNA replication in the hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene in normal human fibroblasts. This PCR method measures the abundance of specific sequences in short fragments of newly replicated DNA from logarithmically growing cells. Quantitative measurements rely on synthetic molecules (competitors) that amplify with the same primer sets as the target molecules, but generate products of different sizes. This method was first utilized to determine the position of the replication origin near the lamin B2 gene (Giacca et al. [1994] Proc. Natl. Acad. Sci. U S A. 91:7119-7123). In the present study, primer sets were tested along a 16-kb region near exon 1 of the HPRT gene. The most abundant fragment was found to be located in the first intron of HPRT, just downstream of the promoter and exon 1 of the gene, and approximately 3.5 kb upstream of a previously reported autonomously replicating sequence (Sykes et al. [1988] Mol. Gen. Genet. 212:301-309).
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PMID:Mapping of an origin of DNA replication near the transcriptional promoter of the human HPRT gene. 1194 90