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)

Two different nucleic acid precursor utilization patterns were obtained for five avian isolates of Chlamydia psittaci. Three of the isolates behaved in a manner similar to that previously described, showing total dependency on the host cell for ribonucleoside triphosphates and being unable to utilize medium-supplied thymidine. In contrast, the other two isolates were incapable of taking pyrimidine ribonucleotides from the host cell and they could efficiently utilize medium-supplied thymidine. These unusual isolates were resistant to 5-fluorouridine while the other three isolates were sensitive. Of the five isolates only 6BC was sensitive to sulfonamides. The five isolates were divided into two groups by comparing the AluI restriction endonuclease patterns obtained following digestion of the major outer membrane protein (OMP1) gene, amplified by the polymerase chain reaction. The OMP1 genotyping results were confirmed by serotyping.
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PMID:Diversity in nucleotide acquisition by antigenically similar Chlamydia psittaci of avian origin. 851 20

Type I topoisomerases alter DNA topology by cleaving and rejoining one strand of duplex DNA through a covalent protein-DNA intermediate. Here we show that vaccinia topoisomerase, a eukaryotic type IB enzyme, catalyzes site-specific endoribonucleolytic cleavage of an RNA-containing strand. The RNase reaction occurs via transesterification at the scissile ribonucleotide to form a covalent RNA-3'-phosphoryl-enzyme intermediate, which is then attacked by the vicinal 2' OH of the ribose sugar to yield a free 2', 3' cyclic phosphate product. Introduction of a single ribonucleoside at the scissile phosphate of an otherwise all-DNA substrate suffices to convert the topoisomerase into an endonuclease. Human topoisomerase I also has endoribonuclease activity. These findings suggest potential roles for topoisomerases in RNA processing.
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PMID:Site-specific ribonuclease activity of eukaryotic DNA topoisomerase I. 965 6

The regulation of mRNA half-lives is determined by multiple factors, including the activity of the messenger RNases (mRNases) responsible for destroying mRNA molecules. Previously, we used cell-free mRNA decay assays to identify a polysome-associated endonuclease that cleaves c-myc mRNA within the coding region. A similar activity has been solubilized and partially purified from a high salt extract of adult rat liver polysomes. Based on a correlation between protein and enzyme activity, the endonuclease is tentatively identified as a approximately 39-kDa protein. It cleaves the coding region stability determinant of c-myc mRNA with considerable specificity. Cleavages occur predominantly in an A-rich segment of the RNA. The endonuclease is resistant to RNase A inhibitors, sensitive to vanadyl ribonucleoside complex, and dependent on magnesium. In these and other respects, the soluble enzyme we have purified resembles the polysome-associated c-myc mRNase.
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PMID:Purification and characterization of a polysome-associated endoribonuclease that degrades c-myc mRNA in vitro. 973 91

The application of small RNA in therapy has been hindered by the lack of an efficient and safe delivery system to target specific cells. Packaging RNA (pRNA), part of the DNA-packaging motor of bacteriophage phi29(Phi29), was manipulated by RNA nanotechnology to make chimeric RNAs that form dimers via interlocking right- and left-hand loops. Fusing pRNA with receptor-binding RNA aptamer, folate, small interfering RNA (siRNA), ribozyme, or another chemical group did not disturb dimer formation or interfere with the function of the inserted moieties. Incubation of cancer cells with the pRNA dimer, one subunit of which harbored the receptor-binding moiety and the other harboring the gene-silencing molecule, resulted in their binding and entry into the cells, and subsequent silencing of anti/proapoptotic genes. The chimeric pRNA complex was found to be processed into functional double-stranded siRNA by Dicer (RNA-specific endonuclease). Animal trials confirmed the suppression of tumorigenicity of cancer cells by ex vivo delivery. It has been reported [Shu, D., Moll, W.-D., Deng, Z., Mao, C., and Guo, P. (2004). Nano Lett. 4:1717-1724] that RNA can be used as a building block for bottom-up assembly in nanotechnology. The assembly of protein-free 25-nm RNA nanoparticles reported here will allow for repeated long-term administration and avoid the problems of short retention time of small molecules and the difficulties in the delivery of particles larger than 100 nm.
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PMID:Specific delivery of therapeutic RNAs to cancer cells via the dimerization mechanism of phi29 motor pRNA. 1614 8

In this issue of Molecular Cell, Guo et al. (2012) demonstrate how a series of sequential posttranslational modifications, phosphorylation, sumoylation, and ubiquitylation, cooperate to target human flap endonuclease FEN1 to degradation by the proteasome at the end of S phase.
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PMID:Ubiquitin, SUMO, and phosphate: how a trio of posttranslational modifiers governs protein fate. 2274 29


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