Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of terminal differentiation on UV-induced DNA damage and its repair in transcriptionally active and inactive genomic sequences was investigated using the murine 3T3-T proadipocyte cell culture system. Actively cycling 3T3-T cells terminally differentiate into adipocytes after exposure to media containing platelet-depleted human plasma. Suitable DNA fragments were analyzed from four genes: beta-actin, adenosine deaminase, dihydrofolate reductase, and lipoprotein lipase. As a result of 3T3-T cell differentiation, lipoprotein lipase and beta-actin expression was modified, whereas adenosine deaminase and dihydrofolate reductase expression was not affected. A DNA fragment representing the transcriptionally inactive locus 70-38 was also evaluated. UV-induced cyclobutane pyrimidine dimers, detected as UV-specific endonuclease-sensitive sites, in each fragment increased linearly as a function of UV dose (0-20 J/m2) independently of gene expression or differentiation. Sequence-specific repair of dimers was measured in stem and terminally differentiated 3T3-T cells after UV irradiation (10 J/m2). For undifferentiated stem cells, the rate and extent of dimer repair was higher in the actively transcribed adenosine deaminase and dihydrofolate reductase genes than in the inactive lipoprotein lipase or 70-38 fragments, the greater difference being observed in the first 8 h post-UV irradiation. In contrast, similar dimer repair rates were found for each DNA fragment in terminally differentiated 3T3-T cells. These data suggest that cellular differentiation is accompanied by a loss of heterogeneity in intragenomic DNA repair.
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PMID:Loss of intragenomic DNA repair heterogeneity with cellular differentiation. 193 6

Lipoprotein lipase (LPL; triacylglycero-protein acylhydrolase, EC 3.1.1.34) was purified from bovine milk. Synthetic oligonucleotides were prepared, based on the amino acid sequences of three peptides obtained from partial digestion of purified LPL, and were used as probes to isolate cDNA clones for LPL mRNA from a bovine mammary gland. One of the clones, pLPL-49R2, contains an insert cDNA (49R2) of about 3.2 kilobases (kb) that hybridizes to all three probes and encodes a polypeptide that includes the NH2-terminal sequence of bovine LPL reported recently [Ben-Avram, C. M., Ben-Zeev, O., Lee, T. D., Hagga, K., Shively, J. E., Goers, J., Pedersen, M. E., Reeve, J. R. & Schotz, M. C. (1986) Proc. Natl. Acad. Sci. USA 83, 4185-4189]. Complete nucleotide sequence analysis revealed that cDNA insert 49R2 contains the entire coding region for LPL as well as a 3' untranslated region of about 1.6 kb. The predicted amino acid sequence indicates that bovine LPL is a hydrophilic protein consisting of 450 amino acids (Mr 50,548) in its unglycosylated form. Blot hybridization analysis of poly(A)+ mRNA from bovine mammary gland demonstrated that there are at least three sizes of LPL mRNAs--3.2, 2.5, and 1.7 kb--with the 2.5-kb mRNA being the most abundant. Restriction endonuclease mapping of other cDNA clones suggested that the variation in mRNA size results from differential utilization of polyadenylylation signals during mRNA processing.
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PMID:Molecular cloning and sequence of a cDNA coding for bovine lipoprotein lipase. 288 34

Direct label alkaline phosphatase (AP) conjugated oligonucleotide probes (AP-DNA) were prepared to assess their utility for allele-specific detection of single base substitutions. Oligonucleotide conjugates were designed to detect point mutations in the genes for lipoprotein lipase (LPL) and coagulation factor-V (FV). Genomic DNA samples, including ones known to harbor point mutations in the genes for LPL and FV, were prepared from whole blood and subjected to polymerase chain reaction (PCR). PCR products were analyzed by Southern hybridization with the allele-specific AP-DNA probes and restriction endonuclease analysis. Thermal profiles for hybridization indicate optimal allele-specific selectivity was achieved with temperatures ranging from 45 degrees C to 55 degrees C at a total Na divided by concentration of 150 mM. Under these conditions the base changes studied were easily discriminated with allele specific hybridization signals in excess of 200:1 as estimated by scanning densitometry. Complete concordance was observed between hybridization and restriction analyses for 175 LPL and 201 FV clinical and reference samples. The total time for analysis of the PCR products was less than 2 h with a dot blot hybridization protocol.
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PMID:Allele-specific hybridization of lipoprotein lipase and factor-V Leiden missense mutations with direct label alkaline phosphatase-conjugated oligonucleotide probes. 893 92

Two missense mutations in exon 6 of the LPL gene were identified on separate alleles in a Dutch patient with lipoprotein lipase (LPL) deficiency. The first mutation is a G1003-->A transition resulting in a D250N mutation, which has been shown previously to result in a catalytically defective protein in patients of French-Canadian ancestry. The second mutation, a C to G transition at nucleotide 1007, predicts a S251C residue change in the highly conserved region of LPL surrounding the loop structure the covers the catalytic triad. This mutation constitutes a novel defect among LPL gene mutations reported so far. Site-directed mutagenesis experiments provide in-vitro evidence for the complete loss of LPL activity resulting from this latter missense mutation. The G1003-->A nucleotide substitution underlying the Asp250 mutation deletes a TaqI endonuclease recognition site and the C1007-->G change that leads to the S251C alteration abolishes a HinfI recognition site. This will facilitate rapid screening for these mutations in LPL-deficient patients.
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PMID:Compound heterozygosity for a known and a novel defect in the lipoprotein lipase gene (Asp250-->Asn; Ser251-->Cys) resulting in lipoprotein lipase (LPL) deficiency. 897 94

Modifications of plasma lipid profile is one of the major causes of a high cardiovascular risk. They can be the consequences of mutations in the gene encoding lipoprotein lipase (LPL), an enzyme that has an important role in the metabolism of plasma lipoproteins. The aim of the present study was to put into practice a method for detecting the Gly188Glu mutation in the LPL gene. The search was performed on a group of 107 patients with cardiovascular diseases and/or dyslipidemias. DNA investigation consisted, in a first stage, in the enzymatic digestion of exon 5 of the LPL gene, previously amplified by the PCR reaction, with the AvaII restriction endonuclease. Three of the subjects were further investigated by the sequencing of exon 5, in order to search for the presence of other mutations. We didn't detect the Gly188Glu mutation in none of the cases, and no other mutation in exon 5 was found in the three patients tested by DNA sequencing. We conclude that the amplification-restriction method can be used for the detection of known mutations in the LPL gene, allowing an early identification of the subjects with a high cardiovascular risk and the onset of the appropriate therapy. In order to detect mutations which don't affect the recognition sequence of a restriction enzyme and eventually new mutations, the sequencing of that gene is recommended.
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PMID:[Method for the molecular diagnosis of lipoprotein lipase genetic deficiency]. 1661 49