Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 2.99 kb mtDNA fragment containing two variable restriction endonuclease sites (EcoRV and XbaI) was subcloned and sequenced from the Mediterranean fruit fly (Ceratitis capitata). This fragment represents approximately one-fifth of the entire mitochondrial sequence. The sequence was aligned with the comparable region from Drosophila yakuba and Anopheles gambiae, resulting in 81.8% and 76.7% identity at the nucleotide level, and 77% and 67.7% identity, respectively, at the amino acid level. The sequenced region includes the complete genes for NADH dehydrogenase 4, NADH dehydrogenase 4L, NADH dehydrogenase 6, and transfer RNAs for proline, threonine and histidine, and part of the genes for NADH dehydrogenase 5 and cytochrome b. Oligonucleotide primers were designed to asymmetrically bracket each of two variable restriction endonuclease sites to allow PCR amplification and subsequent restriction endonuclease analysis of individual fly samples.
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PMID:Analysis of mitochondrial DNA and development of PCR-based diagnostic molecular markers for Mediterranean fruit fly (Ceratitis capitata) populations. 774 77

As part of Rep78/68's involvement in adeno-associated virus (AAV) DNA replication, these highly related, AAV encoded proteins bind to the AAV terminal repeat (TR) DNA and endonucleolytically cleave one strand at the terminal resolution site ("trs" nicking activity) of the TR DNA, a site adjacent to the DNA binding site, 21 bps from the nearest GCTC motif. We have constructed a Rep78 mutant, replacing leucine-threonine at amino acids 64-65 with histidine-methionine (64LH65TM). This mutant, expressed as a chimeric protein with maltose binding protein (MBP), displays Mg++ dependent endonuclease activity, but does not bind to the AAV TR as determined in the conventional electrophoretic mobility shift assay (EMSA). It is also found that wild type MBP-Rep78 endonucleolytically nicks at multiple sites in addition to the previously recognized trs site. These data suggest that the nicking activity is independent of conventional DNA binding activity as measured by EMSA and further suggest that a separate form of DNA recognition by Rep78, not measured by the EMSA, is taking place which allows for endonuclease activity.
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PMID:Dissociation of conventional DNA binding and endonuclease activities by an adeno-associated virus Rep78 mutant. 776 45

A transthyretin mutation was discovered in a French family with familial amyloidotic polyneuropathy originally described in 1983. The syndrome is of early onset (approximate age 35 to 40) with carpal tunnel syndrome. Death is from cardiac disease. By direct genomic DNA sequencing an A-->G mutation was found in the position corresponding to the first base of transthyretin codon 49. The predicted alanine for threonine substitution in the transthyretin protein was proven by amino acid sequencing of transthyretin isolated from the plasma of an affected subject. Since the DNA mutation does not result in the creation or abolition of a restriction endonuclease recognition site, a new DNA analysis technique was used in which site directed mutagenesis is used to create an RFLP when the introduced mutation is in proximity to the natural mutation. Using a 27 nucleotide mutagenesis primer in the PCR reaction, a new Bg1I site was created on amplification of the variant allele. Using this test, termed PCR-IMRA, four affected members of the family were shown to have the mutation.
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PMID:A transthyretin variant (alanine 49) associated with familial amyloidotic polyneuropathy in a French family. 809 1

Analysis of 94 kb of DNA, located between map positions 88 and 182 kb in the 330-kb chlorella virus PBCV-1 genome, revealed 195 open reading frames (ORFs) 65 codons or longer. One hundred and five of the 195 ORFs were considered major ORFs. Twenty-six of the 105 major ORFs resembled genes in the databases including three chitinases, a chitosanase, three serine/threonine protein kinases, two additional protein kinases, a tyrosine protein phosphatase, two ankyrins, an ornithine decarboxylase, a copper/zinc-superoxide dismutase, a proliferating cell nuclear antigen, a DNA polymerase, a fibronectin-binding protein, the yeast Ski2 protein, an adenine DNA methyltransferase and its corresponding DNA site-specific endonuclease, and an amidase. The genes for the 105 major ORFs were evenly distributed along the genome and, except for one noncoding 1788-nucleotide stretch, the genes were close together. Unexpectedly, a 900-bp region in the 1788-bp noncoding sequence resembled a CpG island.
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PMID:Analysis of 94 kb of the chlorella virus PBCV-1 330-kb genome: map positions 88 to 182. 861 77

The process of antigen receptor gene rearrangement, V(D)J recombination, involves DNA cleavage by the RAG-1 and RAG-2 proteins. Cleavage generates covalently sealed (hairpin) DNA ends, termed coding ends, which must be opened by an endonuclease prior to joining. Resolution of these hairpin ends requires the activity of the DNA-dependent protein kinase (DNA-PK), a protein kinase whose specific role is yet undetermined. It has been suggested that phosphorylation of one or both RAG proteins by DNA-PK is required to activate or recruit the hairpin-opening nuclease. Furthermore, very recent work has shown that RAG proteins themselves can open hairpins. These data raise the possibility that DNA-PK-mediated phosphorylation of the RAG proteins could regulate the hairpin opening reaction. To test this hypothesis, we constructed mutant versions of RAG-1 and RAG-2 in which all four DNA-PK consensus phosphorylation sites were removed by site-directed mutagenesis. Our data provide conclusive evidence that phosphorylation of these conserved serine/threonine residues is not required for hairpin opening or joining of V(D)J recombination intermediates.
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PMID:V(D)J recombination catalyzed by mutant RAG proteins lacking consensus DNA-PK phosphorylation sites. 1068 66

An amino acid mutation at residue 284 (Ala to Thr) in the VP2 protein of infectious bursal disease viruses (IBDVs) has been correlated with the ability to replicate in cell culture. In this study, we designed a molecular test for this mutation. The reverse transcriptase/polymerase chain reaction (RT/PCR) was used to amplify a 743-bp region of the VP2 gene that contained the codon for amino acid 284. The restriction endonuclease NgoMIV was selected for this study because the first three nucleotides of its six-base recognition sequence are the codon responsible for the amino acid alanine at residue 284. The RT/PCR products from 10 known pathogenic and 16 vaccine strains of IBDV were examined for the presence or absence of the NgoMIV site. We also examined 189 field strains of IBDV for the NgoMIV site. All 10 known pathogenic IBDV strains contained the NgoMIV site, indicating they contained alanine at residue 284. None of the vaccine strains had the NgoMIV site, suggesting they had threonine or another amino acid at residue 284. The results suggest that the presence of this NgoMIV site can be used as a marker for the identification of wild-type (nonvaccine) IBDV strains. The RT/PCR products from 152 (80.4%) of the field strains had the NgoMIV site and thus have the potential to be wild-type pathogenic viruses. The RT/PCR products from 37 (19.6%) of the field strains were not cleaved by NgoMIV and thus are potentially attenuated vaccine strains. Molecular diagnostic assays have been used to place IBDV strains into genetically related groups. The identification of this genetic marker now makes it possible to identify viruses that are wild-type strains that have the potential to be pathogenic viruses.
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PMID:Use of a genetic marker for wild-type potentially pathogenic infectious bursal disease viruses. 1156 47

Long QT syndrome (LQT) is a cardiovascular disorder causing syncope and sudden death from arrhythmias. Mutations in KCNQ1, KCNH2, KCNE1, KCNE2, and SCN5A genes encoding cardiac potassium and sodium ion channels cause LQT. Two Taiwanese LQT families were screened for mutations in these ion channel genes. In family H87, the diagnosis was made in the 25-year-old female proband and six family members based on recurrent syncope and/or a prolonged QT interval. Genotyping revealed a novel nonsense mutation, R744X (C to T transition in codon 744), in the KCNH2 potassium channel gene, resulting in truncation of the putative cyclic nucleotide-binding domain and C-terminal region of the HERG K(+)-channel in all affected family members. The mutation was confirmed by DdeI endonuclease digestion of the DNA from each family member. The 26-year-old female proband in family L89 developed repeated syncope with QTc of 0.61 seconds. After linkage and mutation analysis, the syndrome in this family was associated with a novel KCNQ1 missense mutation, T309I, causing the substitution of a threonine residue at position 309, in the pore region of the KvLQT1 K(+)-channel, with an isoleucine. By Tsp45I restriction analysis, the mutation was noted in the proband and the proband's asymptomatic brother, but was not detected in 100 unrelated normal individuals. Identification of a mutation has clinical implications for presymptomatic diagnosis and therapy.
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PMID:Linkage and mutation analysis in two Taiwanese families with long QT syndrome. 1180 37

A 249-nucleotide coding region instability determinant (CRD) destabilizes c-myc mRNA. Previous experiments identified a CRD-binding protein (CRD-BP) that appears to protect the CRD from endonuclease cleavage. However, it was unclear why a CRD-BP is required to protect a well-translated mRNA whose coding region is covered with ribosomes. We hypothesized that translational pausing in the CRD generates a ribosome-deficient region downstream of the pause site, and this region is exposed to endonuclease attack unless it is shielded by the CRD-BP. Transfection and cell-free translation experiments reported here support this hypothesis. Ribosome pausing occurs within the c-myc CRD in tRNA-depleted reticulocyte translation reactions. The pause sites map to a rare arginine (CGA) codon and to an adjacent threonine (ACA) codon. Changing these codons to more common codons increases translational efficiency in vitro and increases mRNA abundance in transfected cells. These data suggest that c-myc mRNA is rapidly degraded unless it is (i) translated without pausing or (ii) protected by the CRD-BP when pausing occurs. Additional mapping experiments suggest that the CRD is bipartite, with several upstream translation pause sites and a downstream endonuclease cleavage site.
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PMID:Regulation of c-myc mRNA decay by translational pausing in a coding region instability determinant. 1202 10

Several candidate genes, chosen from the renin- angiotensin system, were examined for their association with essential hypertension. The genes of the renin- angiotensin system (RAS) are good candidates for such an approach because this system is well known to be involved in the control of blood pressure. One of these candidate genes is the gene encoding for angiotensinogen (the most important gene of the RAS associated with essential hypertension in the most population, is the gene for angiotensin-converting enzyme- ACE). One DNA polymorphism within exon 2- with threonine instead of methionine at position 235 (M235T) was found to be significantly associated with hypertension. The objective of this study is the analysis of M235T polymorphism in angiotensinogen gene in Romanian patients with essential hypertension as well as controls. We examined 38 patients with essential hypertension and 21 normotensive patients. In order to identify the M235T angioteninogen variant, we used the following methods: DNA extraction, PCR amplification and enzymatic digestion of the PCR product using Tth 111I restriction endonuclease enzyme. In the study groups, the M235T variant (Met?Thr in aminoacid position 235) was found more frequently in hypertensive patients (81,57%), than in control subjects (66,66%). We identified 52,63% M235T heterozygotes in the hypertensive group compared with 47,61% in the control group, and 28,94% T235T homozygotes in the hypertensive group compared with 19,04% in the control group. The results of our study suggest an association of the M235T polymorphism in the gene encoding angiotensinogen with essential hypertension.
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PMID:Essential arterial hypertension and polymorphism of angiotensinogen M235T gene. 1216 9

Mitochondrial DNA (mtDNA) mutations can cause rare forms of dystonia, but the role of mtDNA mutations in other types of dystonia is not well understood. We now report identification by sequencing, restriction endonuclease analyses, and clonal analyses of a heteroplasmic missense A to G base pair substitution at nucleotide position 3796 (A3796G) in the gene encoding the ND1 subunit of mitochondrial complex I in a patient with adult-onset dystonia, spasticity, and core-type myopathy. The mutation converts a highly conserved threonine to an alanine. The same mutation subsequently was identified in 2 of 74 additional unrelated adult-onset dystonia patients. A muscle biopsy was obtained from 1 of these 2 subjects and this revealed abnormalities of electron transport chain (ETC) activities. The mutation was absent in 64 subjects with early onset dystonia, 82 normal controls, and 65 subjects with Parkinson's disease or multiple system atrophy. The A3796G mutation previously has been reported in 3 of 226 subjects from mitochondrial haplogroup H. Each of the 3 subjects in our study harboring the A3796G mutation was also from haplogroup H. However, a subgroup analysis of haplogroup H subjects from our study indicates that the A3796G mutation is significantly overrepresented among haplogroup H adult-onset dystonia subjects compared with haplogroup H controls (P<0.01). This difference remains significant even after excluding the index patient (P=0.04). These data suggest that, among haplogroup H subjects, the presence of the A3796G mutation increases the risk of developing adult-onset dystonia.
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PMID:A heteroplasmic mitochondrial complex I gene mutation in adult-onset dystonia. 1275 9


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