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:3.1.27.1 (RNase)
16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Infection of BALB/c mouse cells with UV-irradiated herpes simplex virus (HSV) types 1 and 2 resulted in activation of a xenotropic type C virus detected by infectious center formation in permissive rat cells. The levels of type C virus activated by HSV were related to the UV dose and the multiplicity of infection used. The ability of HSV to activate type C virus was eliminated by heat-inactivation and by neutralization with specific antiserum against HSV, but was not affected by purification or treatment with DNase and RNase. Maximum levels of type C virus in the cells and medium were observed within 1 day after HSV infection, and the levels returned to control cell values within 3-4 days. The possible significance of these findings with respect to the putative oncogenic potential of HSV is discussed.
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PMID:Activation of an endogenous mouse type C virus by ultraviolet-irradiated herpes simplex virus types 1 and 2. 17 17

RNA labeled with [methyl-3H]methionine and/or [32P]orthophosphate was isolated from the polyribosomes of herpes simplex virus (HSV) types 1-infected cells and separated into polyadenylylated [poly(A+)]and non-polyadenylylated [poly(A-)] fractions. Virus-specific RNA was obtained by hybridization in liquid to either excess HSV DNA or filters containing immobilized HSV DNA. Analysis in denaturing sucrose gradients indicated that HSV-specific poly(A+) RNA sedimented in a broad peak, with a modal S value of 20. The ratio of [3H]methyl to 32P decreased with increasing size of RNA, suggesting that each RNA chain contains a similar sumber of methyl groups. Further analysis indicated an average of one RNase-resistant structure of the type m7G(5')pppNmpNp or m7G(5')pppNmpNmpNp per 2,780 nucleotides. The following components were identified in the 5'-terminal oligonucleotides of polyribosome-associated HSV-specific poly(A+) and poly(A-) RNA: 7-methylguanosine, N6,2'-O-dimethyladenosine, and the 2'-O-methyl derivatives of guanosine, adenosine, uridine, and denosine, and the 2'-O-methyl derivatives of guanosine, adenosine, uridine, and cytidine. The most common 5'-terminal sequences were m7G(5')pppm6Am and m7G(5')pppGm. An additional modified nucleoside, N6-methyladenosine, was present in an internal position of HSV-specific RNA.
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PMID:5'-Terminal and internal methylated nucleosides in herpes simplex virus type 1 mRNA. 19 8

Synthesis of cellular protein was substantially inhibited within 1 h of infection with herpes simplex virus, type 2, strain G (HSV-2). The inhibition also occurred, although no virus-specific protein synthesis was detected, after infection with u.v. irradiated virus and in cytoplasts that had been enucleated before infection. The inhibitory activity could not be distinguished from infectivity by dilution, sedimentation or reaction with gamma-globulin. HSV-2 also suppresssed the synthesis of Sendai virus proteins, but not those specified by HSV-1. Host protein synthesis was no more sensitive than virus protein synthesis to an increased concentration of NaCl in the medium, nor could the suppression of host synthesis be prevented by adding excess MgCl2 to the medium or by omitting CaCl2 or NaCl. It was accompanied by the breakdown of polyribosomes, which also occurred in the presence of cycloheximide but not at 4 degrees C. The breakdown yielded ribosomes that were sensitive to a high salt concentration, unlike those produced by treatment of polyribosomes with RNase. The synthesis of cellular DNA and RNA was also inhibited following infection with u.v.-inactivated virus. It is concluded that the suppression of host protein synthesis (and probably also of host DNA and RNA synthesis) is caused by a constituent of the infecting virus particles. The mechanism is obscure but probably does not depend on the leakage out of the cell of Mg2+ or into the cell or Ca2+ or Na+ ions, nor on the specific inhibition of initiation of host polypeptide chains, nor on RNase-like attack on host polyribosomes.
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PMID:Suppression of the synthesis of cellular macromolecules by herpes simplex virus. 21 20

Several virion and nonvirion DNAs were tested for the ability to activate endogenous type C virus in BALB/c-derived mouse cells using the calcium precipitation technique. The DNAs from all herpesviruses tested activated xenotropic type C virus synthesis. These included DNAs from herpes simplex virus types 1 and 2, Epstein-Barr virus, human cytomegalovirus, SA8 virus, infectious bovine rhinotracheitis virus, pseudorabies virus, and herpes saimiri virus (M-DNA). In contrast, DNAs from vaccinia virus, simian virus 40, primate cells, bacteria, mycoplasma, and salmon sperm showed no ability to activate type C virus when tested under the same conditions. Several herpesviruses and vaccinia virus, which were highly infectious for the BALB/c cells used, were tested for their ability to activate type C virus after UV irradiation. All herpesviruses tested were positive, while vaccinia virus was negative. Unirradiated simian virus 40 also showed no ability to activate type C virus. Activation of type C virus by DNA from herpes simplex virus was observed after shearing or sonication of the DNA to an average size of 3 x 10(6) daltons, but was not observed with DNA sonicated to an average size of 1 x 10(6) daltons. Alkali denaturation of DNA from herpes simplex virus or treatment with DNase, but not RNase, destroyed its ability to activate type C virus, as did crosslinking of the DNA with 4,5',8-trimethylpsoralen (psoralen) and light.
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PMID:Activation of endogenous type C virus in BALB/c mouse cells by herpesvirus DNA. 21 61

Earlier we reported that herpes simplex virus 1 DNA contains a sequence which binds a host protein in a sequence-specific manner as either a single-stranded or a double-stranded DNA or RNA and that this sequence is located in a transcriptional unit whose RNA traverses the origin of viral DNA replication (OriSRNA) (R.J. Roller, L. McCormick, and B. Roizman, Proc. Natl. Acad. Sci. USA 86:6518-6522, 1989). The protein reacts with both DNA and RNA in band-shift assays and protects the single-stranded RNA sequence from digestion by RNase. We report that the minimal cognate sequence required for these interactions consisted of [N(GTGGGTGGG)2(N less than or equal to 10)]. The ninemer repeat sequence was located at nucleotides -1 to -18 relative to the transcription initiation of the major species of OriSRNA. The activity of the cognate sequence required at least three guanines between thymines and tolerates the insertion of additional thymines, but it was inactivated by the insertion of adenines or by the substitution of some of the guanines with cytosines in one repeat. Replacement of the 10 3' nucleotides has no effect on binding activity, whereas deletion of these sequences abolished it. Among the related sequences with no demonstrable binding activity were some telomeric sequences which interact with known cognate proteins. The electrophoretic mobility of the herpes simplex virus cognate sequences in nondenaturing gels suggests that they may be able to form higher-order structures, but the conditions under which they were formed were different from the optimal conditions for binding the protein. UV light cross-linking studies of labeled RNA-protein complexes following digestion with RNases indicated that the electrophoretic mobility of the protective activity corresponded to that of a protein with an apparent molecular weight of 100,000.
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PMID:Characterization of a herpes simplex virus sequence which binds a cellular protein as either a single-stranded or double-stranded DNA or RNA. 131 59

The influence of fixation and enzymatic digestions on the ability of a denatured double-stranded DNA probe to bind specifically to related sequences of RNA and DNA in sections of Lowicryl embedded cells was investigated. Specificity of the hybridization was assessed using a biotinylated cloned subgenomic herpes simplex virus type 1 DNA fragment to localize viral nucleic acids in sections of infected cells. The probe was detected by anti-biotin antibodies and indirect immunogold labeling. Controls indicated that protease digestion of proteins from the section eliminated non-specific binding of the probe and labeling of endogenous biotin. Both formaldehyde and glutaraldehyde fixation retained viral RNA in protease digested sections. Its labeling was randomly and sparsely distributed over the fibrillo-granular network of the infected nucleus and over the ribosome-rich regions of cytoplasm. Labeling of single-stranded portions of viral DNA in protease-RNase digested sections was infrequent. It was located precisely over nucleoids of a few viral nucleocapsids whatever their location in the cell and their stage of maturation. Labeling of double-stranded viral DNA by denaturation of the DNA in the sections of Lowicryl embedded cells was possible after fixation with formaldehyde but not glutaraldehyde. Among several denaturation protocols, 0.5 N NaOH treatment was best for hybridization of both non-encapsidated and encapsidated viral DNA in protease-RNase digested sections. Free viral genomes were detected exclusively within the virus-replicating region of infected nuclei. Labeling of viral nucleoids was independent of their location in the cell. The high percentage of labeled viral nucleoids suggests that the related viral DNA sequence is not aggregated in the nucleoid but is extended and therefore numerous portions of this defined DNA sequence are accessible at the surface of the section for the binding of the probe.
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PMID:Ultrastructural localization of defined sequences of viral RNA and DNA by in situ hybridization of biotinylated DNA probes on sections of herpes simplex virus type 1 infected cells. 165 2

RNA from the region of the genome encoding herpes simplex virus type 1 latency-associated transcripts (LATs) expressed during lytic infection yields low abundances of both polyadenylated and nonpolyadenylated forms. As has been previously shown for latent infection (A. T. Dobson, F. Sedarati, G. Devi-Rao, W. M. Flanagan, M. J. Farrell, J. G. Stevens, E. K. Wagner, and L. T. Feldman. J. Virol. 63:3844-3851, 1989), all lytic-phase expression of such transcripts requires promoter elements situated approximately 600 bases 5' of the previously mapped 5' end of the poly(A)- forms of LAT. Transient expression experiments revealed no other clear promoter elements within this region, and relatively small amounts of latent-phase transcripts initiating at the same site as observed for lytic-phase LAT could be detected by RNase protection assays. In the lytic phase of infection, the most abundant forms of polyadenylated LAT extended 1,600 bases from the initiation site near the LAT promoter to a potential splice donor site. Poly(A)- LAT species were not recovered in significant amounts from lytically infected neuroblastoma cells, but such RNA from lytically infected rabbit skin cells comapped with poly(A)- LAT from latently infected sensory neurons. Both map between canonical 5' splice donor and 3' splice acceptor site 1,950 bases apart. Poly(A)- LAT cochromatographed with uncapped rRNA on m-aminophenyl boronate agarose under conditions in which capped mRNA was bound. All of these data confirm the previously presented scheme for the expression of poly(A)- LAT as a stable intron derived from the splicing of a large primary transcript; however, we were unable to detect the spliced polyadenylated product of this splicing reaction.
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PMID:Relationship between polyadenylated and nonpolyadenylated herpes simplex virus type 1 latency-associated transcripts. 185 5

The 5' flanking region of the mouse N-ras gene was investigated to determine the elements governing transcriptional activity of the gene. The promoter did not contain typical TATA or CCAAT boxes, and according to primer extension and RNase protection analyses, transcription started at several sites. These assays also confirmed the short nucleotide distance interposed between the N-ras transcription unit and the previously described upstream unr gene. Chromatin studies performed by digestion of nuclei with DNase I revealed the presence of four hypersensitive sites: a, b, c, and d. Deletion mutagenesis of the 5' flanking region revealed sequences responsible for both promotion and inhibition of transcription. These sequences resided within 230 bp upstream of the transcription initiation site. Hypersensitive site b colocalized with the 76-bp segment with promoter activity. The negative regulatory element at position -180 colocalized with hypersensitive site a, was active on the N-ras promoter in stable as well as transient assays, and down-regulated the heterologous herpes simplex virus thymidine kinase promoter. Footprint analysis and in vivo transfection-competition experiments indicated that a trans-acting factor is responsible for the negative effect on transcription. The interaction between the cis-acting negative regulatory element and the promoter region may play a role in the tissue- and developmental-stage-specific patterns of expression of the N-ras gene.
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PMID:Dissection of the mouse N-ras gene upstream regulatory sequences and identification of the promoter and a negative regulatory element. 199 95

Herpes simplex virus 1- and 2 (HSV-1 and HSV-2)-infected cell extracts but not uninfected cell extracts contain an RNA-binding activity for an in vitro-transcribed sequence from the domains of the HSV-1 US11 and alpha 47 genes. The transcript of this sequence has not been detected in infected cells. The binding is sequence and secondary structure specific and protects approximately 95 nucleotides from RNase digestion. Analyses of HSV-1 x HSV-2 recombinants and HSV-1 deletion mutants mapped the function necessary for activity to the US11 or alpha 47 open reading frame. The alpha 47 gene was excluded, since the RNA-binding activity is a late (gamma 2) function dependent on viral DNA synthesis for its expression. The US11 function is the only viral function required, since translation in rabbit reticulocyte lysate of an in vitro-synthesized US11 mRNA resulted in the appearance of the RNA-binding activity. The product of the US11 open reading frame is associated with the RNA probe-protein complex inasmuch as insertion of a sequence encoding in frame 15 additional amino acids at the C terminus of the US11 protein caused a corresponding decrease in the electrophoretic mobility of the binding complex.
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PMID:The herpes simplex virus Us11 open reading frame encodes a sequence-specific RNA-binding protein. 216 49

The exonucleolytic activities associated with herpes simplex virus type-1 (HSV-1) DNA polymerase and DNase were compared. The unique properties of these nucleases were assessed by applying biochemical and immunological methods as well as by genetics. In contrast to the viral DNA polymerase, HSV DNase is equipped with a 5'-3'-exonuclease activity. Under reaction conditions optimal for HSV DNA polymerase, i.e. at high ionic strength, HSV DNase exhibited only limited endonucleolytic activity and degraded double-stranded DNA in a very processive manner and exclusively in the 5'-3' direction, producing predominantly mononucleotides. Both viral enzymes displayed significant RNase activity which could be correlated with the endogenous endonucleolytic and 5'-3'-exonucleolytic activities of the DNase and the polymerase-associated 3'-5' exonuclease. The tight linkage of polymerizing and exonucleolytic functions of the viral DNA polymerase was demonstrated by their identical response to (a) thermal inactivation, (b) drug inhibition and (c) neutralization by polyclonal antibodies reacting specifically with the N-terminal, central and C-terminal polypeptide domains of HSV-1 DNA polymerase. From the data presented it can be concluded that the cryptic 3'-5' exonuclease is the only exonucleolytic activity associated with the viral DNA polymerase.
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PMID:Comparison of exonucleolytic activities of herpes simplex virus type-1 DNA polymerase and DNase. 216 60


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