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)

Posttranscriptional gene silencing allows sequence-specific control of gene expression. Specificity is guaranteed by small antisense RNAs such as microRNAs (miRNAs) or small interfering RNAs (siRNAs). Functional miRNAs derive from longer double-stranded RNA (dsRNA) molecules that are cleaved to pre-miRNAs in the nucleus and are transported by exportin 5 (Exp 5) to the cytoplasm. Adenovirus-infected cells express virus-associated (VA) RNAs, which are dsRNA molecules similar in structure to pre-miRNAs. VA RNAs are also transported by Exp 5 to the cytoplasm, where they accumulate. Here we show that small RNAs derived from VA RNAs (svaRNAs), similar to miRNAs, can be found in adenovirus-infected cells. VA RNA processing to svaRNAs requires neither viral replication nor viral protein expression, as evidenced by the fact that svaRNA accumulation can be detected in cells transfected with VA sequences. svaRNAs are efficiently bound by Argonaute 2, the endonuclease of the RNA-induced silencing complex, and behave as functional siRNAs, in that they inhibit the expression of reporter genes with complementary sequences. Blocking svaRNA-mediated inhibition affects efficient adenovirus production, indicating that svaRNAs are required for virus viability. Thus, svaRNA-mediated silencing could represent a novel mechanism used by adenoviruses to control cellular or viral gene expression.
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PMID:Adenovirus virus-associated RNA is processed to functional interfering RNAs involved in virus production. 1641 15

Adenovirus (Ad) DNA was extracted by the use of Sarkosyl from Ad5-infected HeLa cell nuclei at 15 hr after infection. Mature and replicating viral DNA molecules in the Sarkosyl extract were purified by sucrose gradient centrifugation followed by equilibrium centrifugation in preformed metrizamide gradients. Part of the material was digested with the Hpa I restriction endonuclease and analyzed by electrophoresis through 1% agarose gels. Both terminal fragments D and E did not enter the gel unless first treated with Pronase, suggesting that intracellular viral DNA molecules were linked to proteins by their termini. Examination under the electron microscope of mature intracellular Ad2 or Ad5 DNA molecules extracted with Sarkosyl showed the presence of a majority of circular unit-length molecules. Most of these were attached to a prominent globular structure which disappeared, together with the circularization of the molecule, after treatment with Pronase. We interpret these structures as protein links responsible for the circularization of the molecule. The mature linear DNA molecules observed also showed evidence for linkage structures attached to one or both of their ends. Examination of replicating Ad5 DNA molecules extracted with Sarkosyl revealed the presence of various types of forked, circular molecules, most of which showed evidence for the presence of linkage structures. It is suggested that replicating and newly made Ad DNA molecules are circular inside the cell, perhaps through linkage with proteins, and the possible role of circularization in the replication of viral DNA is discussed.
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PMID:Circular adenovirus DNA-protein complexes from infected HeLa cell nuclei. 1862 74

In the search for the genome of egg drop syndrome virus (EDSV-76) Chinese strain AAV-2, part of restriction endonuclease physical map is analyzed, the complete genomic library is organized. On basis of this, the complete genome nucleotide sequences (32 838 bp in length, including terminal structures) are determined. The data analysis shows: compared with the other Adenoviruses, strain AAV-2 has more disparity on genomic structure and the distribution of open reading frame (ORF). There are no clear E1, E3 and E4 regions in AAV-2 genome. Two segments located at both ends of genome (1.1 kb and 8.3 kb in length respectively) have no homology with the other adenovirus genomes. In addition, strain AAV-2 genome lacks ORFs encoding ElA, pV and pIX, which are common ORFs encoding early, lately proteins in Adenovirus. This reveals differences between EDSA-76, the sole standard strain of group III Avian Adenoviruses, and the other Avian Adenoviruses for the first time. It will help the search for Avian Adenovirus and will also help the search of all Adenoviruses.
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PMID:The complete genomic sequence of egg drop syndrome virus strain AAV-2. 1872 83


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