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)

EcoRI endonuclease digestion of the deoxyribonucleic acid of a phi80 transducing phage carrying the entire tryptophan (trp) operon of Salmonella typhimurium (phi80 S.t.trpE-A) yielded a 4.3 X 10(6)-dalton fragment containing intact trpE, trpD, and trpC and a 3.35 X 10(6)-dalton fragment containing intact trpA. The trpA fragment inserted into EcoRI-cleaved plasmids ColE1 and CR1 was expressed regardless of its orientation of insertion. Mitomycin C, a compound that induces colicin E1 production in ColE1-containing bacteria, stimulated tryptophan synthetase alpha production in cells containing ColE1-TRPA plasmids with the trpA fragment inserted in one orientation but not the other. We conclude that in the inducible plasmids trpA can be expressed from the colicin E1 promoter.
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PMID:Mitomycin C-induced expression of trpA of Salmonella typhimurium inserted into the plasmid ColE1. 31 46

The density of CR1 (the C3b receptor, CD35) on erythrocytes from normal individuals is determined by a codominant bi-allelic system associated with a single base mutation within an intron of the CR1 structural gene, leading to an additional polymorphic HindIII endonuclease site. The CR1 genotype is determined by HindIII digestion of genomic DNA and Southern blotting. We have developed a method based on polymerase chain reaction (PCR) amplification of the genomic DNA fragment of interest followed by HindIII endonuclease digestion and agarose gel electrophoresis which permits a more rapid and reliable determination of the CR1 genotype. The method is suitable for large scale clinical studies in diseases with altered expression of CR1 on erythrocytes.
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PMID:Genomic determination of the CR1 (CD35) density polymorphism on erythrocytes using polymerase chain reaction amplification and HindIII restriction enzyme digestion. 167 71

A 34-kb restriction endonuclease map of the region associated with an endogenous virus integration site and K, the gene that confers sex-linked late-feathering (LF) in chickens, is presented. Hybridizations of genomic blots of DNA from early-feathering and LF White Leghorns indicated that the region also contains additional repetitive elements upstream from a chicken repetitive (CR1) element. This extended map and the probes described should be useful in identifying the molecular alterations associated with this locus.
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PMID:A restriction enzyme map of the sex-linked late-feathering locus of chickens. 750 96

The present study investigated the expressed number of CR1 on erythrocytes (E) in relationship of the CR1 density genotype from 46 patients with systemic lupus erythematosus (SLE) and 47 healthy volunteers. The CR1 genotype was determined by a method based on polymerase chain reaction (PCR) amplification of the genomic DNA fragment of 1.8 kb separated by HindIII endonuclease digestion and agarose gel electrophoresis. Our data supported the earlier results that the number of binding sites/E for monoclonal anti-CR1 decreased among SLE patients compared with normal individuals having the same alleles for the CR1/E density. At the same time the novelty of our recent results was that the decreased expression of CR1 on E correlated significantly with kidney involvement in patients homozygous for the CR1/E high density allele (HH). These data suggest that the deficiency of the detectable number of CR1 on erythrocytes is acquired in this SLE population.
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PMID:CR1 density polymorphism and expression on erythrocytes of patients with systemic lupus erythematosus. 916

RTE-1 is a non-long-terminal-repeat (non-LTR) retrotransposable element first found in the Caenorhabditis elegans genome. It encodes a 1,024-amino-acid open reading frame (ORF) containing both apurinic-apyrimidic endonuclease and reverse-transcriptase domains. A possible first ORF of only 43 amino acids overlaps with the larger ORF and may be the site of translation initiation. Database searches and phylogenetic analysis indicate that representatives of the RTE clade of non-LTR retrotransposons are found in the bovine and sheep genomes of mammals and in the silkmoth and mosquito genomes of insects. In addition, the previously identified SINEs, Art2 and Pst, from ruminate and viper genomes are shown to be truncated RTE-like retrotransposable elements. RTE-derived SINE elements are also found in mollusc and flatworm genomes. Members of the RTE clade are characterized by unusually short 3' untranslated regions that are predominantly composed of AT-rich trimer, tetramer, and/or pentamer repeats. This study establishes RTE as a very widespread clade of non-LTR retrotransposons. RTE represents the third distinct class of non-LTR retrotransposons in the vertebrate lineage (after Line 1 elements in mammals and CR1 elements in birds and reptiles).
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PMID:The RTE class of non-LTR retrotransposons is widely distributed in animals and is the origin of many SINEs. 972 77

This study describes the consensus sequence of a full-length (4585bp) non-LTR retrotransposon from the fugu fish, Fugu rubripes. The retrotransposon, termed Maui, is represented by a group of very similar LINE elements found as multiple copies within the fish genome. Two long open reading frames (ORFs) are predicted from the sequence. The first ORF has a domain resembling a novel zinc finger motif recently found in both a turtle and a chicken (CR1) non-LTR retrotransposon. The second ORF includes sequences homologous to the endonuclease, reverse transcriptase and carboxy-terminal domains found in other non-LTR retrotransposons. Sequence comparisons of the predicted translation products of the two ORFs indicate that Maui is most closely related to a class of non-LTR retrotransposons represented by the CR1-like elements (chicken repeat 1 elements) that are present in several avian species and have recently been described in the turtle Platemys spixii. The sequence of the 3' untranslated region also supports this relationship since Maui resembles the CR1 like elements in not having a poly-A tail.
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PMID:A LINE element from the pufferfish (fugu) Fugu rubripes which shows similarity to the CR1 family of non-LTR retrotransposons. 1002 50

Most active non-LTR (long terminal repeat) retrotransposons carry two open reading frames (ORFs) encoding ORF1p and ORF2p proteins. The ORF2p proteins are relatively well studied and are known to contain endonuclease/reverse transcriptase domains. At the same time, the biological function of ORF1p proteins remains poorly understood, except in that they nonspecifically bind single-stranded mRNA/DNA molecules. CR1-like elements form the most widely distributed clade/superfamily of non-LTR retrotransposons. We found that ORF1p proteins encoded by diverse CR1-like elements contain conserved esterase domain (ES) or plant homeodomain (PHD). This indicates that CR1-like ORF1p proteins are either lipolytic enzymes or are involved in protein-protein interactions related to chromatin remodeling. Sequence conservation of ES suggests that interaction with cellular membranes is an important phase in life circles of CR1-like elements. Presumably such interaction helps in penetrating host cells. As a consequence, the presence of multiple young CR1 families characterized by approximately 10% intrafamily and 40% interfamily identities may be explained by a relatively frequent horizontal transfer of these CR1-like elements. Unexpectedly, ES links together non-LTR retrotransposons and single-stranded RNA viruses like influenza C and coronaviruses, which are known to depend on their own ES.
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PMID:The esterase and PHD domains in CR1-like non-LTR retrotransposons. 1251 4

BfCR1 is the first non-long terminal repeat retrotransposon to be characterised in the amphioxus genome. Sequence alignment of the predicted translation product reveals that BfCR1 belongs to the CR1-like retroposon class, a family widely distributed in vertebrate and invertebrate lineages. Structural analysis shows conservation of the specific motifs of the ORF2-CR1 elements: the N-terminal endonuclease, the reverse transcriptase and the C-terminal domains. The BfCR1 element possesses an atypical 3' terminus consisting of the tandem repeat (AAG)6. We gathered evidence supporting the mobility of this element and report an estimated 15 copies of BfCR1, mostly truncated, per haploid genome, a remarkably low number when compared to that of vertebrates. Phylogenetic analysis, including the amphioxus element, seems to indicate that (i) CR1-like retroposons cluster in a monophyletic group and (ii) the CR1-like family was already present in the chordate ancestor. Our data provide further support for the horizontal transmission of CR1-like elements during early vertebrate evolution.
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PMID:The first non-LTR retrotransposon characterised in the cephalochordate amphioxus, BfCR1, shows similarities to CR1-like elements. 1278 27

Autonomous non-long terminal repeat retrotransposons (NLRs) are ubiquitous mobile genetic elements that insert their DNA copies at new locations by retrotransposition. In vertebrates, there are 4 NLR clades, L1, L2, CR1, and RTE, which diverged in the Precambrian era. It has been demonstrated that retrotransposition of L1 and L2 members proceeds via coordinated reactions of targeted DNA cleavage and reverse transcription catalyzed by the NLR-encoded proteins, which are followed by the joining of the 5' (upstream) junction. However, the study on the mobility pathways for vertebrate NLRs is so far limited to L1 and L2. In this report, using target analysis of nested transposons for genomic copies, we studied retrotransposition pathways for a variety of vertebrate NLRs, including those of the L1, L2, CR1, and RTE clades in the human, cow, opossum, chicken, and zebrafish genomes. Thus, this study constitutes the first comprehensive analysis of NLR retrotransposition products in vertebrates. Our data revealed that these elements share similar mechanisms for the cleavages of the 2 target DNA strands and for the initiation of reverse transcription. Possible endonuclease-independent insertions were also identified. Overall, our results suggest the existence of multiple retrotransposition pathways that are conserved among the diverse NLR clades in various vertebrate hosts.
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PMID:Mobility pathways for vertebrate L1, L2, CR1, and RTE clade retrotransposons. 1834 91

Retrotransposons including CR1 (chicken repeat 1) elements are important factors in genome evolution. They also mobilize in a genome in a way that makes them useful for phylogenetic analysis and species identification. This study was designed to identify lineages of CR1 elements in the genomes of forensically important oestroid flies and to further characterize one family, Sbul.CR1B. CR1 fragments from several taxa were amplified, cloned, sequenced and analyzed to identify different lineages of elements. A variety of retrotransposon families were recovered that exhibit similarity to known retrotransposon families. A number of these lineages may have given rise to taxon-specific subfamilies that have been recently active in oestroid fly genomes. One element from Sarcophaga bullata was analyzed in detail to reconstruct a partial Open Reading Frame containing both the reverse transcriptase (RT) and endonuclease (EN) domains. These domains were used to identify conserved amino acid regions in the recovered consensus via comparison to known non-LTR retrotransposons. Phylogenetic analysis of the RT domain revealed the recovered ORF in S. bullata compares favorably with previously documented CR1-like elements. This work will serve as the basis for additional analyses targeted at developing a simple, efficient marker system for the identification of forensically important carrion flies.
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PMID:Multiple chicken repeat 1 lineages in the genomes of oestroid flies. 1971 65


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