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:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nucleotide sequence of a 2549-bp DNA fragment containing the entire coding region of the marmoset herpesvirus (MarHV) thymidine kinase gene (tk) and the flanking sequences was determined by the dideoxynucleotide chain termination method. The MarHV thymidine kinase polypeptide predicted from the nucleotide sequence contained 376 amino acids and had a molecular weight of 41,281. The sequencing data also reveal that the coding portion of another MarHV gene probably begins only 292 nucleotides downstream from the stop codon of the MarHV tk gene. There was relatively little nucleotide sequence homology between the MarHV tk gene and that of the herpes simplex virus (HSV) types 1 and 2 tk genes. Comparisons of the predicted amino acid sequences of the MarHV thymidine kinase polypeptide with that of the HSV-1 and HSV-2 thymidine kinase polypeptides, however, revealed clear, but interrupted, homology within several regions of the polypeptide chains. Amino acid sequence homology was particularly striking at residues 10 to 27 of the MarHV thymidine kinase polypeptide and residues 49 to 66 of the HSV-1 and HSV-2 thymidine kinase polypeptides. These same amino acid residues exhibit noticeable sequence homology to the mitochondrial beta subunit ATPase, oncogene p21 protein, adenylate kinase, and to other nucleotide-binding proteins. It has been proposed that the indicated regions of homology are elements of a nucleotide-binding pocket in ATPase, p21, and adenylate kinase, raising the possibility that amino acid residues 15 to 25 of the MarHV thymidine kinase and 54 to 64 of the HSV-1 and HSV-2 enzymes are likewise parts of nucleotide-binding sites.
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PMID:Nucleotide sequence of the marmoset herpesvirus thymidine kinase gene and predicted amino acid sequence of thymidine kinase polypeptide. 633 Sep 76

Simian virus 40 (SV40) large T antigen can immortalize a wide variety of mammalian cells in culture. We have taken advantage of this property of T antigen to use it as a carrier for the expression of cytotoxic T-lymphocyte (CTL) recognition epitopes. DNA sequences corresponding to an H-2Db-restricted SV40 T-antigen site I (amino acids 205 to 215) were translocated into SV40 T-antigen DNA at codon positions 350 and 650 containing EcoRI linkers. An H-2Kb-restricted herpes simplex virus glycoprotein B epitope (amino acids 498 to 505) was also expressed in SV40 T antigen at positions 350 and 650. Primary C57BL/6 mouse kidney cells were immortalized by transfection with the recombinant and wild-type T-antigen DNA. Clonal isolates of cells expressing chimeric T antigens were shown to be specifically susceptible to lysis by CTL clones directed to SV40 T-antigen site I and herpes simplex virus glycoprotein B epitopes, indicating that CTL epitopes restricted by two different elements can be processed, presented, and recognized by the epitope-specific CTL clones. Our results suggest that SV40 T antigen can be used as a carrier protein to express a wide variety of CTL epitopes.
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PMID:Simian virus 40 T antigen as a carrier for the expression of cytotoxic T-lymphocyte recognition epitopes. 769 88

Rb represses E2F-mediated transcription in part by blocking the trans-activation domain of E2F. In addition, Rb can convert an E2F binding site from a positive to a negative element. To examine the effect of a Rb-DNA-bound complex on transcription, full-length Rb was fused to the DNA binding domain of GAL4. Here, we report that GAL4-Rb can repress transcription mediated by either Sp1, AP-1, or p53, dependent upon the presence of both the GAL4 DNA binding domain and GAL4 binding sites. Moreover, GAL4-Rb inhibited the activity of the herpes simplex virus tk promoter from GAL4 binding sites located at a distance from the promoter. In contrast, GAL4-Rb was unable to repress basal transcription. Cotransfection of specific cyclins and cyclin-dependent kinases or SV40 T-antigen abolished the repressive activity of GAL4-Rb. The domains of Rb involved in mediating the repression of transcription were mapped to regions that are overlapping, but not identical, to those required for the interaction with E2F. We propose that Rb can function as a general repressor of transcription when bound to the promoter region.
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PMID:The retinoblastoma susceptibility gene product represses transcription when directly bound to the promoter. 772 91

The herpes simplex virus helicase-primase complex, a heterotrimer of the UL5, UL8, and UL52 proteins, displays a single predominant site of primer synthesis on phi X174 virion DNA (Tenney, D. J., Hurlburt, W. W., Micheletti, P. M., Bifano, M., and Hamatake, R. K. (1994) J. Biol. Chem. 269, 5030-5035). This site was mapped and found to be deoxycytosine-rich, directing the synthesis of a primer initiating with several guanine residues. The size and sequence requirements for primer synthesis were determined using oligonucleotides containing variations of the predominant template. Although the efficiency of primer synthesis on oligonucleotides was influenced by template size, it was absolutely dependent on nucleotide sequence. Conversely, the ATPase activity on oligonucleotide templates was dependent on template size rather than nucleotide sequence. Furthermore, only oligonucleotides containing primase templates were inhibitory in a coupled primase-polymerase assay using phi X174 DNA as template, suggesting that primer synthesis or primase turnover is rate-limiting. Additionally, stimulation of helicase-primase by the UL8 component and that by the ICP8 protein were shown to differ mechanistically using different templates: the UL8 component stimulated the rate of primer synthesis on phi X174 virion DNA and oligonucleotide templates, while ICP8 stimulation occurred only on phi X174 virion DNA.
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PMID:Sequence-dependent primer synthesis by the herpes simplex virus helicase-primase complex. 772 27

The herpes simplex virus type 1 (HSV-1) origin binding protein (UL9 protein) interacts specifically with the HSV-1 encoded single strand DNA-binding protein ICP8 (Boehmer, P.E. and Lehman, I.R. (1994) Proc. Natl. Acad. Sci. U.S.A. 90, 8444-8448). A UL9 mutant protein (UL9DM27) that lacks the C-terminal 27 amino acids shows normal origin-specific DNA binding and retains its DNA-dependent ATPase and helicase activities, but has a greatly reduced affinity for ICP8. The extreme C-terminal portion of the UL9 protein is therefore required for ICP8 binding. The helicase activity of the UL9DM27 protein is approximately 8-fold greater than that of the wild type UL9 protein and is not stimulated by ICP8. The UL9DM27 protein has a reduced ability to replicate origin-containing plasmids in vivo. Consequently, the interaction between the UL9 protein and ICP8 is likely to be important for origin-dependent DNA replication in vivo, presumably to promote efficient unwinding of the DNA at an HSV-1 origin of DNA replication.
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PMID:Association of origin binding protein and single strand DNA-binding protein, ICP8, during herpes simplex virus type 1 DNA replication in vivo. 796 4

Rabbit cornea (control or infected with herpes virus) was studied at different time periods after the infection. The change of both ultrastructure and topochemistry of lactate dehydrogenase, adenosine triphosphatase, 5'-nucleotidase is found. The alteration of phosphohydrolase ultracytochemistry is probably due to the enzyme mechanisms which are responsible for reproduction of the herpes simplex virus. Further study of herpetic keratitis enzymology will allow better understanding of the pathogenesis and improve the treatment of herpetic keratitis.
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PMID:[Ultrastructural and ultracytochemical analysis of herpes infected cornea]. 798 38

In this study we evaluated modifications of various structural and functional properties of the plasma membrane of HeLa S3 cells following infection by the lytic virus herpes simplex virus type 1 (HSV-1). Na+/K(+)-ATPase activity considerably decreased during the first few hours post-infection (p.i.), whereas Na+ and K+ concentrations were not significantly affected until a much later period. By 8 h p.i., a partial membrane depolarization in infected cells had occurred, as indicated by a small change in the transmembrane potential. HSV infection induced a time-dependent lipid peroxidation of HeLa cell plasma membranes temporally correlated with the progressive reduction in Na+/K(+)-ATPase activity. Moreover, a significant decrease of membrane fluidity appeared at a late phase of the viral replicative cycle probably representing cumulative membrane damage. These results demonstrate that HSV-1 infection induced the production of free radicals in non-phagocytic cells. Since lipid peroxidation begins at an early stage of the virus replicative cycle, it may be directly related to viral cytopathicity.
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PMID:Effects of herpes simplex virus type 1 infection on the plasma membrane and related functions of HeLa S3 cells. 799 28

To determine the effect of the major DNA adduct, the intrastrand d(GpG) cross-link, produced by the antitumor drug cis-diamminedichloroplatinum(II) on the activity of a helicase known to be essential for DNA replication, we have examined its interaction with the origin-binding protein (UL9 protein) of herpes simplex virus type-1. We found that the helicase activity of the UL9 protein is inhibited only when the adduct is present on the template strand along which the protein translocates. This effect was paralleled by a comparable inhibition of the UL9 protein's DNA-dependent ATPase activity. The inhibitory effect of the lesion can be reduced by the addition of the herpes simplex virus type-1 single-stranded DNA-binding protein, ICP8. This stimulatory effect is specific for ICP8 and appears to be the result of the functional and physical interaction that is known to exist between the UL9 protein and ICP8, and not due to the preferential interaction of ICP8 with the adduct.
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PMID:Effect of the major DNA adduct of the antitumor drug cis-diamminedichloroplatinum (II) on the activity of a helicase essential for DNA replication, the herpes simplex virus type-1 origin-binding protein. 806 11

The herpes simplex virus type 1 (HSV) UL5, UL8, and UL52 proteins form a helicase-primase complex in infected cells. Several laboratories have demonstrated that helicase and nucleoside triphosphatase activities of the heterotrimer (UL5/8/52) are indistinguishable from that of a subassembly of UL5 and UL52 (UL5/52). Although the UL5/52 subassembly functions in coupled primase-polymerase assays on homopolymeric templates, its activity on natural DNA templates has been reported to require UL8. To determine the role of UL8 in primase assays, the activity of the UL5/52 subassembly was compared to that of the heterotrimer reconstituted by adding UL8 to UL5/52. We detected significant activity of the UL5/52 subassembly in coupled primase-polymerase and oligoribonucleotide primer synthesis assays on phi X174 and M13 virion DNAs. However the addition of UL8 to UL5/52 stimulated this activity in a dose-dependent manner. We demonstrate that stimulation occurred at the level of primer synthesis. UL8 did not affect the amount or size of primers annealed to template, their utilization by DNA polymerase, or the use of specific initiation sites within the template. In kinetic studies, the rate of primer synthesis was increased by UL8 but the Km for phi X174 DNA template was unchanged. These results suggest that a function of the UL8 component of the HSV helicase-primase complex is to increase the efficiency of primer synthesis by UL5/52.
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PMID:The UL8 component of the herpes simplex virus helicase-primase complex stimulates primer synthesis by a subassembly of the UL5 and UL52 components. 810 78

The UL52 gene product of herpes simplex virus type 1 (HSV-1) comprises one subunit of a 3-protein helicase-primase complex that is essential for replication of viral DNA. The functions of the individual subunits of the complex are not known with certainty, although it is clear that the UL8 subunit is not required for either helicase or primase activity. Examination of the predicted amino acid sequence of the UL5 gene reveals the existence of conserved helicase motifs; it seems likely, therefore, that UL5 is responsible for the helicase activity of the complex. We have undertaken mutational analysis of UL52 in an attempt to understand the functional contribution of this protein to the helicase-primase complex. Amino acid substitution mutations were introduced into five regions of the UL52 gene that are highly conserved among HSV-1 and the related herpesviruses equine herpesvirus 1, human cytomegalovirus, Epstein-Barr virus, and varicella-zoster virus. Of seven mutants analyzed by an in vivo replication assay, three mutants, in three different conserved regions of the protein, failed to support DNA replication. Within one of the conserved regions is a 6-amino-acid motif (IL)(VIM)(LF)DhD (where h is a hydrophobic residue), which is also conserved in mouse, yeast, and T7 primases. Mutagenesis of the first aspartate residue of the motif, located at position 628 of the UL52 protein, abolished the ability of the complex to support replication of an origin-containing plasmid in vivo and to synthesize oligoribonucleotide primers in vitro. The ATPase and helicase activities were unaffected, as was the ability of the mutant enzyme to support displacement synthesis on a preformed fork substrate. These results provide experimental support for the idea that UL52 is responsible for the primase activity of the HSV helicase-primase complex.
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PMID:Helicase-primase complex of herpes simplex virus type 1: a mutation in the UL52 subunit abolishes primase activity. 818 7


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