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:3.1.27.5 (RNase)
17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Simian varicella virus (SVV) causes a natural, varicella-like disease in nonhuman primates. The unique short region of the SVV genome contains four open reading frames (ORFs), two of which encode glycoproteins that exhibit extensive homology with varicella-zoster virus (VZV) gpIV (gI) and gpI (gE). Northern hybridization, primer extension, and RNase protection analyses were employed to define precisely the transcripts mapping to the SVV gpIV and gpI genes. A total of five transcripts composing two coterminal families of RNAs were mapped to the SVV gpIV and gpI ORF region. Based on transcriptional mapping and previous DNA sequence analysis, two transcripts 1.3 and 2.2 kb in size were assigned to the SVV gpIV and gpI genes, respectively. The transcriptional patterns described in this study for the SVV gpIV and gpI ORFs are analogous to those previously reported for the homologous glycoproteins genes encoding the herpes simplex virus type 1 Us7 (gI) and Us8 (gE) and VZV gpIV and gpI genes. In addition, the transcriptional start site for the VZV gpI RNA was determined. DNA alignments of the promoter regions for the SVV and VZV gpIV and gpI genes revealed a number of cis-acting elements which are conserved between the two viruses. The characterization of SVV glycoprotein genes will facilitate future studies to define their role in SVV pathogenesis and immunity and assist in the construction of recombinant vaccines which could be evaluated in the simian varicella model.
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PMID:Transcriptional analysis of two simian varicella virus glycoprotein genes which are homologous to varicella-zoster virus gpI (gE) and gpIV (gI). 797 31

Unlike other small animals, cytomegalovirus (CMV) infection of the guinea pig results in transplacental passage and intrauterine infection of the fetus. These features make the guinea pig model ideal for studying vaccine strategies designed to prevent congenital infection. Unfortunately, little is known about immunogenic guinea pig CMV gene products. In other animal cytomegaloviruses, a major target of the host immune response is the glycoprotein B (gB, gp UL 55) gene product. Using DNA probes containing human CMV gB sequences, the gB gene homolog of the guinea pig cytomegalovirus was identified, cloned, and sequenced. The gpCMV gB gene maps to a region spanning portions of the HindIII K, Q, and P fragments of the gpCMV genome. DNA sequence analysis identified an open reading frame of 2706 nucleotides capable of encoding a protein of 901 amino acids. Extensive similarity to the human and murine gB proteins was noted with 42% identity at the amino acid level. The predominant gpCMV gB mRNA is a 6.8-kb transcript with the expression kinetics of an early gene. RNase protection and primer extension analyses indicated that gB mRNAs were transcribed from two different initiation sites corresponding to distinct TATA elements. Polyclonal antisera prepared against a synthetic peptide derived from amino acid sequences within the ORF identified a 58-kDa virion-associated protein representing the cleaved COOH-terminus (gp 58) of the gpCMV gB molecule. The molecular characterization of gpCMV gB should facilitate studies of vaccine strategies in the guinea pig model of congenital CMV infection.
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PMID:Cloning and characterization of the guinea pig cytomegalovirus glycoprotein B gene. 800 31

Gametophytic self-incompatibility in the Solanaceae is controlled by a single, multiallelic locus, the S locus. We have recently described an allele of the S locus of Lycopersicon peruvianum that caused this normally self-incompatible plant to become self-compatible. We have now characterized two glycoproteins present in the styles of self-compatible and self-incompatible accessions of L. peruvianum: one is a ribonuclease that cosegregates with a functional self-incompatibility allele (S6 allele); the other cosegregates with the self-compatible allele (Sc allele) but has no ribonuclease activity. The derived amino acid sequences of the cDNAs encoding the S6 and Sc glycoproteins resemble sequences of other ribonucleases encoded by the S locus. The derived sequence for the Sc glycoprotein differs from the others by lacking one of the histidine residues found in all other S-locus ribonucleases. These findings demonstrate the essential role of ribonuclease activity in self-incompatibility and lend further weight to evidence that this histidine residue is involved in the catalytic site of the enzyme.
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PMID:Loss of a histidine residue at the active site of S-locus ribonuclease is associated with self-compatibility in Lycopersicon peruvianum. 802 14

The genetic and antigenic variability of the G glycoproteins from 76 human respiratory syncytial (RS) viruses (subgroup A) isolated during six consecutive epidemics in either Montevideo, Uruguay, or Madrid, Spain, have been analyzed. Genetic diversity was evaluated for all viruses by the RNase A mismatch cleavage method and for selected strains by dideoxy sequencing. The sequences reported here were added to those published for six isolates from Birmingham, United Kingdom, and for two reference strains (A2 and Long), to derive a phylogenetic tree of subgroup A viruses that contained two main branches and several subbranches. During the same epidemic, viruses from different branches were isolated. In addition, closely related viruses were isolated in distant places and in different years. These results illustrate the capacity of the virus to spread worldwide, influencing its mode of evolution. The antigenic analysis of all isolates was carried out with a panel of anti-G monoclonal antibodies that recognized strain-specific (or variable) epitopes. A close correlation between genetic relatedness and antigenic relatedness in the G protein was observed. These results, together with an accumulation of amino acid changes in a major antigenic area of the G glycoprotein, suggest that immune selection may be a factor influencing the generation of RS virus diversity. The pattern of RS virus evolution is thus similar to that described for influenza type B viruses, expect that the level of genetic divergence among the G glycoproteins of RS virus isolates is the highest reported for an RNA virus gene product.
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PMID:Evolutionary pattern of human respiratory syncytial virus (subgroup A): cocirculating lineages and correlation of genetic and antigenic changes in the G glycoprotein. 805 27

Bovine respiratory syncytial virus (BRSV) is a very important pathogen of cattle and perhaps other ruminants. It is a major contributor to the incidence of respiratory tract disease in nursing beef and feedlot and dairy calves. The genome of respiratory syncytial viruses encodes 10 proteins translated from 10 unique mRNAs. The major glycoprotein (G), fusion protein (F), 1A protein and the 22K protein are components of the viral envelope. The nucleocapsid contains the nucleocapsid protein (N), the phosphoprotein (P), and the large protein (L). The matrix protein (M) forms a structural layer between the envelope and the nucleocapsid. Antibodies to all the structural proteins develop in convalescent calves. However, evidence suggests that immunity develops primarily as a result of the antigenic stimulus by the major glycoprotein G and the fusion glycoprotein F. It is known also that activated cytotoxic T cells interact with N and F protein antigens and helper T cells interact with N, F, and 1A protein antigens. With the exception of the major glycoprotein, the respective proteins of various respiratory syncytial viruses share major antigenic domains. Based on antigenic differences of the major glycoprotein, at least 3 subgroups of RSV are recognized; human A, human B, and bovine RSV. Indirect evidence suggests that a second subgroup of BRSV exists. However, we have identified only one BRSV subgroup based on our work with RNase mismatch cleavage analysis of the G protein gene from a limited number of strains. Furthermore, our data indicated that a caprine RSV isolate is closely related to the bovine strains, but an ovine isolate is not. The latter may constitute yet another subgroup of RSV. These data affect decisions on optimization of immunoprophylaxis since evidence suggests that protection against a homologous RSV subgroup virus is superior to that against a heterologous strain in immune subjects.
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PMID:Antigenic diversity of respiratory syncytial viruses and its implication for immunoprophylaxis in ruminants. 811 89

It is seven years since the first reports of cDNAs encoding pistil glycoproteins that segregated with particular S-alleles. During this time, the S-glycoproteins of the Solanaceae have been identified as RNases. This enzymatic activity relies on the presence of histidine residues at the putative active site of the RNase, and these are conserved in all S-glycoproteins so far characterized. The proteins also contain "hypervariable" regions that may have some role in allelic specificity. It is particularly interesting that putative S-glycoproteins from Japanese pear, which is from a different family, the Rosaceae, are also RNases. To counter the temptation to extrapolate to other families with gametophytic self-incompatibility, there is evidence that in another family, the Papaveraceae, poppy S-glycoproteins are not RNases. The current evidence is consistent with a process in which the S-RNase moves into the incompatible pollen tube and degrades RNA, including rRNA. As rRNA genes are not transcribed in pollen, the resulting degradation would lead to the death of the cell. But still we are left with some important gaps in our knowledge. How does the S-RNase move across the wall and membrane and into the pollen tube? How is the specificity of the interaction controlled? What is the mechanism of signal transduction? A major bottleneck in unraveling the story is understanding the nature of the S-locus product in pollen. Is it related to the stylar S-locus product or is it the product of a different gene in the same locus? Each question underlines the sketchiness of our knowledge of many plant processes that are not specific to pollination, but that we need to understand if we are to work out the details of self-incompatibility. For example, we have a very incomplete understanding of cell wall synthesis generally and pollen wall synthesis in particular. How do macronutrients move through cell walls to the cytoplasm of cells generally and pollen tubes in particular? What is the nature of the receptor-ligand interaction in plant cells generally and pollen tubes in particular? A similar range of questions and gaps in our knowledge exist in the sporophytic system, exemplified by studies in Brassica spp. In this case, we have no known enzymatic or other function for the stigmatic S-glycoproteins. We do, however, know that the S-locus in Brassica includes at least two genes, one encoding a S-glycoprotein and the other encoding a protein kinase.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Molecular aspects of self-incompatibility in flowering plants. 812 4

Herpes simplex virus type 1 (HSV-1) expresses a unique series of RNA molecules, the latency-associated transcripts or LATs, during latent infection of neuronal tissues. Previous studies by others have described a TATA box-containing latency-active promoter, referred to here as LAP1, located approximately 700 bp upstream of the 5' end of the major 2.0-kb LAT. In this report, transient gene expression assays were employed to identify a second, novel latency-active promoter (LAP2) present within a region downstream of LAP1 and 5' proximal to the major 2.0-kb LAT. In contrast to LAP1, this promoter lacks a TATA box but possesses cis-acting regulatory elements and other features frequently observed within eukaryotic housekeeping gene promoters. Unlike most other HSV promoters, LAP2 was down-regulated by the viral transcriptional activators ICP4 and ICP0. The majority of LAP2-positive regulatory elements were located within sequences from -257 to -58 relative to the 5' end of the 2.0-kb LAT, and the basal promoter mapped within sequences from -14 to +28. RNase protection experiments demonstrated that chimeric LAT-chloramphenicol acetyltransferase transcripts produced in the transient assays initiated at or near the 5' end of the major 2-kb LAT. Tn5 insertional mutagenesis of the ICP4 regulatory gene determined that down-regulation of LAP2 required the ICP4 transactivating domain and targeted the minimal promoter region as the site of action by ICP4. Replicating recombinant viruses containing a LAP2-lacZ reporter gene cassette in an ectopic site (glycoprotein C locus) were shown to be active in mouse trigeminal ganglia. Taken together, these experiments suggest that the LAT region of the HSV-1 genome contains at least two latency-active promoters which may play different roles in expressing the various LATs. Alternatively, these promoters may comprise a larger promoter-regulatory complex which may influence transcription during latency.
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PMID:A novel latency-active promoter is contained within the herpes simplex virus type 1 UL flanking repeats. 813 9

Conglutinin and mannan-binding protein are serum proteins that have similar carbohydrate binding specificities toward high mannose-type oligosaccharides, and yet only conglutinin binds the complement glycoprotein iC3b, which contains oligosaccharides of this type. In the present study, the interactions of conglutinin and mannan-binding protein were evaluated with the complement glycoprotein C3, including various physiologically derived fragments of this glycoprotein, and neoglycolipids prepared from oligosaccharides released from C3 and its isolated alpha and beta chains. Several conclusions can be drawn. First, the interaction of conglutinin is profoundly influenced by the state of the protein moiety of the alpha chain in the vicinity of the glycosylation site Asn-917. Second, the binding to the C3-derived glycoprotein iC3b appears to be exclusively mediated through the Man8 or Man9 oligosaccharide on the alpha chain; there is no evidence for other N-linked oligosaccharides on C3 that are uniquely bound by conglutinin. Third, although conglutinin shows a more restricted binding relative to mannan-binding protein toward the oligosaccharides free of protein, it has a broader binding pattern toward the oligosaccharides as presented on C3-derived glycoproteins. From these and additional observations with RNase B, which contains high mannose-type oligosaccharides at Asn-34, it is clear that the protein moieties of these glycoproteins markedly influence the presentation of the oligosaccharides such that biological specificity is mediated by the commonly occurring high mannose-type oligosaccharides in the context of specific carrier proteins.
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PMID:Differential recognition by conglutinin and mannan-binding protein of N-glycans presented on neoglycolipids and glycoproteins with special reference to complement glycoprotein C3 and ribonuclease B. 815 87

The ovine lentiviruses cause encephalitis, pneumonia, and arthritis in sheep worldwide. Visna virus is a prototype of this family and the pathogenesis and molecular biology of the virus has been well characterized. The envelope proteins of visna virus are responsible for binding of virus to host cells and for causing cell fusion. The surface glycoprotein also elicits cellular and humoral immune responses to the virus, the former being thought to be responsible for eliminating infected cells as well as causing inflammatory lesions. In this study, transgenic sheep were constructed that expressed the envelope genes of visna virus under the control of the visna LTR to investigate the role of the env gene in the pathogenesis of lentiviral disease in its natural host. Three transgenic lambs were identified that contain the env transgene and express the envelope glycoproteins. These transgenic animals have remained healthy and expression of the viral gene has had no obvious deleterious effect. Expression of the visna envelope protein was demonstrated by cell fusion mediated by the envelope gene as well as by immunoprecipitation of the envelope proteins with monoclonal antibodies and immunofluorescence analyses of Env protein in cells. The target cell for visna virus replication in infected animals is the monocyte/macrophage. In natural infection, the level of viral gene expression in these cells increases with cell maturation. In the transgenic sheep, monocytes did not express the envelope glycoproteins until they differentiated into macrophages in vitro. Expression of the env mRNA in macrophages was quantitated by an RNase protection assay. In addition to expression in macrophages, the transgene was expressed by fibroblasts isolated from skin of the transgenic sheep. Expression of both the Env and Rev proteins was detected by immunoprecipitation and immunofluorescence. Two of the three lambs responded immunologically to the expression of the transgene by producing binding antibodies to the envelope glycoproteins. Thus, these transgenic sheep provide a model to study whether a lentivirus glycoprotein will prevent infection or modulate disease in its natural host after virus challenge.
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PMID:Development of transgenic sheep that express the visna virus envelope gene. 817 28

Murine coronaviruses such as mouse hepatitis virus (MHV) infect mouse cells via cellular receptors that are isoforms of biliary glycoprotein (Bgp) of the carcinoembryonic antigen gene family (G. S. Dveksler, C. W. Dieffenbach, C. B. Cardellichio, K. McCuaig, M. N. Pensiero, G.-S. Jiang, N. Beauchemin, and K. V. Holmes, J. Virol. 67:1-8, 1993). The Bgp isoforms are generated through alternative splicing of the mouse Bgp1 gene that has two allelic forms called MHVR (or mmCGM1), expressed in MHV-susceptible mouse strains, and mmCGM2, expressed in SJL/J mice, which are resistant to MHV. We here report the cloning and characterization of a new Bgp-related gene designated Bgp2. The Bgp2 cDNA allowed the prediction of a 271-amino-acid glycoprotein with two immunoglobulin domains, a transmembrane, and a putative cytoplasmic tail. There is considerable divergence in the amino acid sequences of the N-terminal domains of the proteins coded by the Bgp1 gene from that of the Bgp2-encoded protein. RNase protection assays and RNA PCR showed that Bgp2 was expressed in BALB/c kidney, colon, and brain tissue, in SJL/J colon and liver tissue, in BALB/c and CD1 spleen tissue, in C3H macrophages, and in mouse rectal carcinoma CMT-93 cells. When Bgp2-transfected hamster cells were challenged with MHV-A59, MHV-JHM, or MHV-3, the Bgp2-encoded protein served as a functional MHV receptor, although with a lower efficiency than that of the MHVR glycoprotein. The Bgp2-mediated virus infection could not be inhibited by monoclonal antibody CC1 that is specific for the N-terminal domain of MHVR. Although CMT-93 cells express both MHVR and Bgp2, infection with the three strains of MHV was blocked by pretreatment with monoclonal antibody CC1, suggesting that MHVR was the only functional receptor in these cells. Thus, a novel murine Bgp gene has been identified that can be coexpressed in inbred mice with the Bgp1 glycoproteins and that can serve as a receptor for MHV strains when expressed in transfected hamster cells.
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PMID:Bgp2, a new member of the carcinoembryonic antigen-related gene family, encodes an alternative receptor for mouse hepatitis viruses. 820 27


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