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Purifoy DJ, Beauchamp LM, de Miranda P, Ertl P, Lacey S, Roberts G, Rahim SG, Darby G, Krenitsky TA, Powell KL. Review of research leading to new anti-herpesvirus agents in clinical development: valaciclovir hydrochloride (256U, the L-valyl ester of acyclovir) and 882C, a specific agent for varicella zoster virus. J Med Virol 1993; Suppl 1:139-45. [PMID: 8245881 DOI: 10.1002/jmv.1890410527] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Research leading to the new anti-herpesvirus compounds discussed here has come from three approaches. The first approach was directed towards improving the bioavailability of acyclovir by examining the potential of a variety of prodrugs, leading to the new compound valaciclovir hydrochloride. The second approach was to examine a large number of 5-substituted pyrimidines for activity against those viruses which were not as potently inhibited by acyclovir as are herpes simplex viruses, i.e., varicella zoster virus (VZV) and human cytomegalovirus (HCMV). This research led to the new chemical entity 882C for VZV. A third approach has been to examine drug combinations with acyclovir. This research led to the compound 348U, an inhibitor of herpes simplex virus ribonucleotide reductase which acts synergistically in combination with acyclovir. This manuscript will focus on the first two approaches leading to new compounds valaciclovir hydrochloride and 882C since Dr. Safrin details such background for 348U/acyclovir. Attempts to improve the bioavailability of acyclovir began a decade ago. Early prodrugs were compounds with alterations in the 6-substituent of the purine ring of acyclovir. The 6-amino congener required the cellular enzyme adenosine deaminase for conversion to acyclovir and the 6-deoxycongener was dependent on cellular xanthine oxidase for conversion. Neither of these prodrugs had a chronic toxicity profile in laboratory animals as good as acyclovir. Efforts were directed towards simpler esters and 18 amino acid esters were made. The pharmacokinetic profile of each prodrug was determined in rats by measuring the recovery of acyclovir in urine after oral dosing.(ABSTRACT TRUNCATED AT 250 WORDS)
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Ertl PF, Powell KL. Physical and functional interaction of human cytomegalovirus DNA polymerase and its accessory protein (ICP36) expressed in insect cells. J Virol 1992; 66:4126-33. [PMID: 1318399 PMCID: PMC241215 DOI: 10.1128/jvi.66.7.4126-4133.1992] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Expression of the human cytomegalovirus (HCMV) (AD169) DNA polymerase gene under the control of the polyhedrin promoter of Autographa californica nuclear polyhedrosis virus in Spodoptera frugiperda (Sf9) cells has provided a source of highly active CMV DNA polymerase. In extracts from CMV-infected cells, the CMV DNA polymerase is found strongly associated with an additional polypeptide, ICP36. This protein has been identified as the CMV homolog of the herpes simplex virus type 1 UL42 gene product and may have a similar function. We have expressed HCMV DNA polymerase and ICP36 in the same system and demonstrated that they interact to form a stable complex. Moreover, ICP36 functions to stimulate the DNA polymerase activity in a template-dependent manner. We have compared the activity of the recombinant DNA polymerase in the presence and absence of ICP36 on a number of DNA templates and measured the effect of the polymerase inhibitors phosphonoformic acid and acyclovir triphosphate.
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Suzutani T, Lacey SF, Powell KL, Purifoy DJ, Honess RW. Random mutagenesis of the thymidine kinase gene of varicella-zoster virus. J Virol 1992; 66:2118-24. [PMID: 1312622 PMCID: PMC289003 DOI: 10.1128/jvi.66.4.2118-2124.1992] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
To understand the relationship between the primary structure and function of varicella-zoster virus thymidine kinase (VZV TK; EC 2.7.1.21), we established rapid screening and phenotypic selection of mutant VZV TK genes in TK-deficient Escherichia coli C600 by using a constitutive pKK223-3 expression plasmid. In this screening system, mutant TK genes generated by random mutagenesis were identified by the sensitivity of E. coli-expressing VZV TKs to 5-bromo-2'-deoxyuridine and 1-beta-D-arabinofuranosyl-E-5-(2-bromovinyl) uracil. Twenty-four mutant clones with amino acid substitutions were isolated, and their nucleotide sequence and enzymatic activities were determined. Of the 24 clones, 20 had single amino acid substitutions, 2 clones had double amino acid substitutions, and 1 clone had triple amino acid substitutions. In 17 cases of single amino acid substitution, six mutations led to lost enzyme activity, and four of these six mutations centered in the ATP-binding site. The other 11 mutations resulted in reduction of both TK and thymidylate kinase activities or only thymidylate kinase activity and were located in scattered positions in the VZV TK gene, although 5 mutations showed a tendency to cluster in the region between positions 251 and 260.
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Thomas MS, Gao M, Knipe DM, Powell KL. Association between the herpes simplex virus major DNA-binding protein and alkaline nuclease. J Virol 1992; 66:1152-61. [PMID: 1309895 PMCID: PMC240819 DOI: 10.1128/jvi.66.2.1152-1161.1992] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Herpes simplex virus encodes seven proteins which have been shown to be both necessary and sufficient for in vitro replication of origin-containing plasmids. We have shown previously that one of these proteins, the major DNA-binding protein mDBP, forms a complex with alkaline nuclease, which is not one of the seven essential proteins. In this study, we have employed immunological reagents and a series of deletion mutants to investigate this complex further. We have determined the regions of mDBP which are important in the formation of this complex, and we have shown that the intranuclear locations of alkaline nuclease and major DNA-binding protein overlap.
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Ertl PF, Thomas MS, Powell KL. High level expression of DNA polymerases from herpesviruses. J Gen Virol 1991; 72 ( Pt 7):1729-34. [PMID: 1649906 DOI: 10.1099/0022-1317-72-7-1729] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The DNA polymerase genes of human cytomegalovirus (HCMV) and varicella-zoster virus (VZV) were inserted separately into the polyhedrin gene of Autographa californica nuclear polyhedrosis virus (AcNPV) by cotransfection of Spodoptera frugiperda (SF9) cells with baculovirus transfer vectors carrying the genes and AcNPV infectious DNA. Infection of SF9 cells with the recombinant viruses resulted in expression from the polyhedrin promoter of proteins of the expected Mrs. These proteins possessed DNA polymerase activities similar to that of the enzymes induced by the respective herpesvirus in infected cells, and were identified as HCMV and VZV DNA polymerase using inhibitors and specific antisera reactive with each enzyme.
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31
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Lacey SF, Suzutani T, Powell KL, Purifoy DJ, Honess RW. Analysis of mutations in the thymidine kinase genes of drug-resistant varicella-zoster virus populations using the polymerase chain reaction. J Gen Virol 1991; 72 ( Pt 3):623-30. [PMID: 1848597 DOI: 10.1099/0022-1317-72-3-623] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We have applied the polymerase chain reaction (PCR) technique to analyse mutations in the thymidine kinase (TK) gene of varicella-zoster virus (VZV) associated with resistance to the 5-bromovinyl (BVaraU) and 5-propynyl (PYaraU) analogues of arabinofuranosyl deoxyuridine. The results from this study allow three clear conclusions to be drawn. Firstly, the technique clearly shows that populations of VZV derived from plaque purification were truly clonal only when the plaques were initiated from cell-free virus (representing a tiny fraction of infectious virus) and plaques initiated by infected cells contained a mixture of variants. Secondly, despite the background mutations caused by errors of the Taq DNA polymerase, mutations relevant to drug resistance can easily be distinguished. The BVaraU-resistant mutant, 7-1, contained an aspartic acid to asparagine mutation at residue 18 and a single base deletion (position 65298 of the VZV DNA sequence), resulting in a frameshift and premature termination of the polypeptide chain, was found in the BVaraU-resistant mutant YSR. PYaraU-resistant virus populations contained viruses with one or more of three independent mutations, i.e. single base substitutions resulting in mutations from leucine to proline at residue 92, histidine to arginine at residue 97 and a deletion of 20bp (residues 65,135 to 65,154). Finally, the technique has uncovered novel sites in the virus TK associated with drug resistance. We conclude that in vitro amplification using the PCR combined with cloning and sequencing is a relatively rapid method for identifying mutations in small virus populations even when they are not homogeneous.
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32
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Powell KL, Purifoy DJ. Derivation of new drugs for therapy of AIDS. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1991; 309A:33-40. [PMID: 1724111 DOI: 10.1007/978-1-4899-2638-8_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Hart BL, Powell KL. Antibacterial properties of saliva: role in maternal periparturient grooming and in licking wounds. Physiol Behav 1990; 48:383-6. [PMID: 2125128 DOI: 10.1016/0031-9384(90)90332-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Canine saliva was tested for its bactericidal effects against pathogens relevant to the presumed hygienic functions of maternal grooming of the mammary and anogenital areas and licking of wounds. Both female and male saliva were bactericidal against Escherichia coli and Streptococcus canis but only slightly, and nonsignificantly, bactericidal against coagulase positive staphylococcus and Pseudomonas aeruginosa. E. coli is the cause of highly fatal coliform enteritis of neonatal mammals and E. coli and S. canis are the main pathogens implicated in neonatal septicemia of dogs. The bactericidal effects of saliva would facilitate the hygienic function of maternal licking of the mammary and anogenital areas in protecting newborns from these diseases. E. coli and S. canis along with coagulase positive staphylococcus and P. aeruginosa are among the common wound contaminants of dogs. Wound licking, and the application of saliva, would thus reduce wound contamination by E. coli and S. canis. The resistance of staphylococcus to bactericidal effects of saliva may be a factor in the high frequency (46 percent) with which coagulase positive staphylococcus was isolated from wounds compared with much lower frequency (9-17 percent) with which E. coli and S. canis were isolated.
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34
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Tisdale M, Larder BA, Lowe DM, Stammers DK, Purifoy DJ, Ertl P, Bradley C, Kemp S, Darby GK, Powell KL. Structural characterization of HIV reverse transcriptase: a target for the design of specific virus inhibitors. J Antimicrob Chemother 1989; 23 Suppl A:47-54. [PMID: 2469675 DOI: 10.1093/jac/23.suppl_a.47] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The reverse transcriptase (RT) of HIV is an important target for chemotherapy as demonstrated by the effective treatment of AIDS patients with zidovudine, a potent inhibitor of RT. Structural studies of HIV RT were therefore undertaken with a view to designing more effective inhibitors. To obtain sufficient quantities of enzyme for these studies the reverse transcriptase gene of HIV was cloned into a high level expression plasmid yielding reverse transcriptase at a level of 10% of the total Escherichia coli proteins. Monoclonal antibodies to RT were raised in mice and have been used to purify the enzyme by immunoaffinity chromatography. Crystallization of the enzyme has been achieved and studies are underway to determine its three-dimensional structure. In addition, carboxy-terminal truncated mutants were prepared by inserting stop codons into the gene at appropriate sites. The proteins expressed were analysed for RT and RNase H activity and used for mapping RT epitopes. This, together with previous data on site-directed mutagenesis of conserved regions of HIV RT has helped to map some of the structural and functional regions of the enzyme.
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35
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Lowe DM, Aitken A, Bradley C, Darby GK, Larder BA, Powell KL, Purifoy DJ, Tisdale M, Stammers DK. HIV-1 reverse transcriptase: crystallization and analysis of domain structure by limited proteolysis. Biochemistry 1988; 27:8884-9. [PMID: 2466481 DOI: 10.1021/bi00425a002] [Citation(s) in RCA: 124] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Bacterially expressed recombinant HIV-1 reverse transcriptase is active as both a homodimer of Mr 66,000 subunits and a heterodimer of Mr 66,000 and 51,000 subunits. The heterodimer is formed by cleavage of a C-terminal fragment from one Mr 66,000 polypeptide, which occurs during purification and crystallization of reverse transcriptase. Thus, crystals obtained from purified Mr 66,000 polypeptide preparations consisted of an apparently equimolar mixture of Mr 66,000 and 51,000 polypeptides, which were apparently analogous to the Mr 66,000 and 51,000 polypeptides detected in HIV-infected cells and in virions. Limited proteolysis of the homodimer with alpha-chymotrypsin also resulted in cleavage to a stable Mr 66,000/51,000 mixture, and proteolysis with trypsin resulted in the transient formation of some Mr 51,000 polypeptide. These results are consistent with the reverse transcriptase molecule having a protease-sensitive linker region following a structured domain of Mr 51,000. Further digestion with trypsin resulted in cleavage of the Mr 51,000 polypeptide after residue 223, yielding peptides of apparent Mr 29,000 and 30,000. A minor peptide of Mr 40,000 was also produced by cleavage of the Mr 66,000 polypeptide after residue 223. About half the original Mr 66,000 polypeptides remained resistant to proteolysis and existed in complex with the above peptides in solution. During both chymotrypsin and trypsin digestion there was an increase in the reverse transcriptase activity caused by a doubling of Vmax with little change in Km for dTTP.(ABSTRACT TRUNCATED AT 250 WORDS)
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36
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Tisdale M, Ertl P, Larder BA, Purifoy DJ, Darby G, Powell KL. Characterization of human immunodeficiency virus type 1 reverse transcriptase by using monoclonal antibodies: role of the C terminus in antibody reactivity and enzyme function. J Virol 1988; 62:3662-7. [PMID: 2458486 PMCID: PMC253508 DOI: 10.1128/jvi.62.10.3662-3667.1988] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We describe the production of eight monoclonal antibodies reactive with human immunodeficiency virus type 1 reverse transcriptase (RT) by immunization of mice with purified recombinant RT. These antibodies were found to react with one or the other of two regions of the enzyme and were found to be useful in immunodeficiency purification of large amounts of the enzyme. One epitope located at the C terminus of the enzyme was of particular interest, since it was present in only the larger, 66-kilodalton (kDa) RT species and not its smaller, 51-kDa counterpart. To define this epitope, a series of mutants was made which synthesized C-terminally truncated RT. These mutants indicated that the same region of the enzyme, when deleted, both removed the C-terminal epitope and drastically reduced RT activity, indicating the importance of this region in the function of the enzyme; however, even the 51-kDa enzyme component had demonstrable activity.
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37
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Larder BA, Purifoy DJ, Powell KL, Bradley C, Kemp S, Tisdale M, Ertl P, Darby GK, Stammers D. Structural studies of the acquired immunodeficiency syndrome virus reverse transcriptase. Am J Med 1988; 85:173-5. [PMID: 2457314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The clinical success of zidovudine has established the human immunodeficiency virus (HIV) reverse transcriptase (RT) as a valid target for the design of drugs to treat acquired immunodeficiency syndrome. In order to facilitate structural studies of this enzyme, expression systems in Escherichia coli, which allow the production of large amounts of RT, have been established. Using this recombinant material the RT has been purified and crystallized. Crystallographic studies currently underway are aimed at elucidating the three-dimensional structure of HIV RT. The availability of a bacterial expression system has enabled structural/functional studies of the RT by site-directed mutagenesis. These studies have identified amino acid residues that are essential for activity of the enzyme and might be involved in substrate binding. It is hoped that structural information of this nature will allow the rational design of HIV RT inhibitors.
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38
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Littler E, Halliburton IW, Powell KL, Snowden BW, Arrand JR. Immunological conservation between Epstein-Barr virus and herpes simplex virus. J Gen Virol 1988; 69 ( Pt 8):2021-31. [PMID: 2841414 DOI: 10.1099/0022-1317-69-8-2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We have analysed Epstein-Barr virus (EBV)- and herpes simplex virus (HSV)-infected cells for evidence of antigenic conservation of virus-coded proteins. Immunofluorescence and Western blot analyses of EBV-transformed cell lines demonstrated the presence of proteins that are antigenically related to the HSV alkaline DNase, infected cell-specific protein 34/35, glycoprotein B, thymidine kinase and the major DNA-binding protein. These proteins were characterized on the basis of Mr and possible kinetic class.
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39
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Thomas MS, Banks LM, Purifoy DJ, Powell KL. Production of antibodies of predetermined specificity against herpes simplex virus DNA polymerase and their use in characterization of the enzyme. J Virol 1988; 62:1550-7. [PMID: 2833607 PMCID: PMC253181 DOI: 10.1128/jvi.62.5.1550-1557.1988] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Peptides from preselected regions of the herpes simplex virus DNA polymerase were used to generate monospecific antisera to defined regions of the enzyme. The antisera were used to localize the polymerase within the infected cell and to determine the time of synthesis during productive infection. Comparison with a neutralizing polyclonal antiserum was used to show the specificity of the peptide antisera. By using the antisera the stabilities of the DNA polymerase, the alkaline nuclease, and the major DNA-binding protein were determined, and the state of phosphorylation of the DNA polymerase was compared with each of these proteins.
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40
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Larder BA, Purifoy DJ, Powell KL, Darby G. Site-specific mutagenesis of AIDS virus reverse transcriptase. Nature 1987; 327:716-7. [PMID: 2439916 DOI: 10.1038/327716a0] [Citation(s) in RCA: 277] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Human immunodeficiency virus (HIV) is the causative agent of AIDS (acquired immune deficiency syndrome) a disease which poses a serious challenge to modern medicine. If we are to conquer this disease we will need a protective vaccine or effective drugs able to block the life cycle of the virus. An early stage in the invasion of the host cell is the conversion of the RNA genome of the virus to a double-stranded DNA intermediate which subsequently becomes integrated into the host cell chromosome. The enzyme reverse transcriptase is crucial in this process and is thus an obvious chemotherapeutic target. In this study we have used site-directed mutagenesis of this enzyme expressed in Escherichia coli to reveal several important functional regions of the protein including putative components of the triphosphate binding site and pyrophosphate exchange sites.
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41
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Littler E, Zeuthen J, McBride AA, Trøst Sørensen E, Powell KL, Walsh-Arrand JE, Arrand JR. Identification of an Epstein-Barr virus-coded thymidine kinase. EMBO J 1986; 5:1959-66. [PMID: 3019675 PMCID: PMC1167064 DOI: 10.1002/j.1460-2075.1986.tb04450.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We have demonstrated the presence of an Epstein-Barr virus (EBV)-coded thymidine kinase (TK) by producing biochemically transformed, TK-positive mammalian cell lines using either microinjection of whole EBV virions or calcium phosphate-mediated transfection of the SalI-B restriction endonuclease fragment of EBV DNA. Analysis of these cell lines showed that: (i) EBV DNA was present in the cell lines, (ii) sequences from the SalI-B restriction endonuclease fragment of EBV were expressed, (iii) a TK activity was present and (iv) a protein with antigenic cross-reactivity with the herpes simplex virus (HSV) TK was produced. The identity of the EBV TK gene was determined by demonstrating that a recombinant plasmid, which expressed the protein product of the BXLF1 open reading frame as a fusion protein, could complement TK- strains of E. coli. A comparison of the predicted amino acid sequences of the TK proteins of EBV and HSV-1 revealed significant regions of homology.
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42
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Vaughan PJ, Purifoy DJ, Powell KL. DNA-binding protein associated with herpes simplex virus DNA polymerase. J Virol 1985; 53:501-8. [PMID: 2578573 PMCID: PMC254663 DOI: 10.1128/jvi.53.2.501-508.1985] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Purified preparations of herpes simplex virus type 2 DNA polymerase made by many different laboratories always contain at least two polypeptides. The major one, of about 150,000 molecular weight, has been associated with the polymerase activity. The second protein, of about 54,000 molecular weight, which we previously designated ICSP 34, 35, has now been purified. The purified protein has been used to prepare antisera (both polyclonal rabbit serum and monoclonal antibodies). These reagents have been used to characterize the protein, to demonstrate its quite distinct map location from that of the DNA polymerase on the herpes simplex virus genome, and to demonstrate the close association between the two polypeptides.
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43
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Snowden BW, Kinchington PR, Powell KL, Halliburton IW. Antigenic and biochemical analysis of gB of herpes simplex virus type 1 and type 2 and of cross-reacting glycoproteins induced by bovine mammillitis virus and equine herpesvirus type 1. J Gen Virol 1985; 66 ( Pt 2):231-47. [PMID: 2981966 DOI: 10.1099/0022-1317-66-2-231] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
An antiserum was produced to the oligomeric form of glycoprotein B (gB) induced by herpes simplex virus type 1 (HSV-1) strain 17. This antiserum gave a single common precipitin line in agar gel immunodiffusion with HSV-1, HSV-2, bovine mammillitis virus (BMV) and equine herpesvirus type 1 (EHV-1). It also neutralized HSV-1, HSV-2 and BMV but not EHV-1. Absorption of the antiserum with excess HSV-2 or BMV antigen resulted in an HSV-1-specific neutralizing antiserum. In immunoprecipitation, two proteins, gB and pgB, were precipitated from HSV-1- and HSV-2-infected cells and at least three from BMV- and EHV-1-infected cells. Glycoprotein B and pgB of three HSV-1 and three HSV-2 strains and the corresponding antigenically related glycoproteins of BMV- and EHV-1-infected cells were labelled with 125I, digested with trypsin and the resulting peptides separated by two-dimensional thin-layer chromatography or high-pressure liquid chromatography. The resulting profiles were found to be almost identical, suggesting considerable structural conservation of the peptide backbone of the antigenically related glycoproteins of these four viruses.
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44
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Banks LM, Halliburton IW, Purifoy DJ, Killington RA, Powell KL. Studies on the herpes simplex virus alkaline nuclease: detection of type-common and type-specific epitopes on the enzyme. J Gen Virol 1985; 66 ( Pt 1):1-14. [PMID: 2578550 DOI: 10.1099/0022-1317-66-1-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Five monoclonal antibodies to the alkaline nuclease of herpes simplex virus (HSV) types 1 and 2 have been used in immunoperoxidase tests to demonstrate the nuclear localization of the enzyme within HSV-1- and HSV-2-infected cells and to purify the enzyme from cells infected with either virus by immunoadsorbant chromatography. Affinity chromatography with a 32P-labelled extract of HSV-2-infected cells has enabled us to demonstrate that the nuclease eluting from the immunoadsorbant is a phosphoprotein, hence confirming the nuclease to be identical to the phosphorylated polypeptide previously referred to as ICSP 22 (HSV-2) or ICP 19 (HSV-1). In addition, the results clearly demonstrate that monoclonal antibodies Q1, CC1 and CH2 are directed against HSV type-common epitopes while V1 and T2T1 antibodies are against HSV-2-specific epitopes on the enzyme. Using the type-specific monoclonal antibodies in an immunoperoxidase test, the enzyme specified in cells infected with intertypic recombinants has been typed; correlation of these data with restriction endonuclease maps of the recombinants has enabled us to map the position of the active site of the nuclease gene to map units 0.168 to 0.184 on the genomes of both HSV-1 and HSV-2. Taken with the data mapping the mRNA encoding this enzyme, the nuclease active site can be mapped to 0.168 to 0.175 on the genome. Finally, the use of monoclonal antibodies in immunofluorescence tests on infected cells has demonstrated that the nuclease is synthesized within 2 h post-infection.
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45
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Vaughan PJ, Banks LM, Purifoy DJ, Powell KL. Interactions between herpes simplex virus DNA-binding proteins. J Gen Virol 1984; 65 ( Pt 11):2033-41. [PMID: 6094715 DOI: 10.1099/0022-1317-65-11-2033] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Monoclonal antibodies directed against several herpes simplex virus (HSV)-induced DNA-binding proteins were used to investigate protein interactions in HSV-infected cells. Q1 monoclonal antibody, which is specific for the HSV-induced alkaline nuclease, when used in an immunoadsorbant column resulted in the purification of the alkaline nuclease, to which large quantities of the major DNA-binding protein were bound. Conversely, when a monoclonal antibody to the major DNA-binding protein was used in affinity chromatography other polypeptides (including the DNA polymerase and alkaline nuclease) were eluted in addition to the major DNA-binding protein. Similar results were obtained when the experiment was performed using a monoclonal antibody to another HSV-2 DNA-binding protein. These results suggest the possibility that these polypeptides interact as part of the HSV DNA replication complex, and this hypothesis is discussed.
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46
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Banks LM, Vaughan PJ, Meredith D, Powell KL. Monoclonal antibodies to herpes simplex virus thymidine kinase. J Gen Virol 1984; 65 ( Pt 9):1625-30. [PMID: 6088685 DOI: 10.1099/0022-1317-65-9-1625] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Purified herpes simplex virus thymidine kinase has been used to immunize mice for the production of monoclonal antibodies to the enzyme. Monoclonal antibodies were successfully produced against both herpes simplex virus type 1 and type 2 enzymes. These antibodies should prove useful for detecting the enzyme under a variety of experimental conditions. We also demonstrate that the antibodies can provide an alternative method for obtaining large amounts of purified thymidine kinase.
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47
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Costa RH, Draper KG, Banks L, Powell KL, Cohen G, Eisenberg R, Wagner EK. High-resolution characterization of herpes simplex virus type 1 transcripts encoding alkaline exonuclease and a 50,000-dalton protein tentatively identified as a capsid protein. J Virol 1983; 48:591-603. [PMID: 6313961 PMCID: PMC255390 DOI: 10.1128/jvi.48.3.591-603.1983] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Four partially overlapping mRNAs (1.9, 2.3, 3.9, and 4.5 kilobases [kb]) were located between 0.16 and 0.19 map units on the herpes simplex virus type 1 genome. Their direction of transcription was found to be from right to left. The 2.3-kb mRNA was found to be early (beta), whereas the others were late (beta gamma). Partial sequence analysis of the DNA encoding these genes indicated that the promoter for the 2.3-kb mRNA shares structural features with other early (beta) promoters. In vitro translation of hybrid-selected mRNA indicated that among the proteins these mRNAs encode are an 82,000-dalton (d) polypeptide reactive with a monoclonal antibody against herpes simplex virus type 2 alkaline exonuclease and a 50,000-d polypeptide weakly reactive with a polyclonal antibody made against the capsid protein VP19C. Further experiments suggested that the 2.3-kb mRNA encodes the 82,000-d polypeptide, whereas one (or both) of the larger mRNAs encodes the 50,000-d protein. A novel finding was that the 1.9-kb mRNA appears to share part of the translational reading frame for alkaline exonuclease, but any polypeptide it encodes does not react with the monoclonal antibody to this enzyme.
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Banks L, Purifoy DJ, Hurst PF, Killington RA, Powell KL. Herpes simplex virus non-structural proteins. IV. Purification of the virus-induced deoxyribonuclease and characterization of the enzyme using monoclonal antibodies. J Gen Virol 1983; 64 (Pt 10):2249-60. [PMID: 6311954 DOI: 10.1099/0022-1317-64-10-2249] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The alkaline nucleases induced by herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) have been purified from high salt extracts of virus-infected cells. The purification used three types of column chromatography and resulted in apparently homogeneous DNase preparations with good recovery. The enzyme from HSV-2-infected cells has been characterized. It had both exonuclease and endonuclease activity, each with an unusually high pH optimum. The enzyme had an absolute requirement for magnesium which could not be replaced by other divalent cations. Analysis of the sedimentation characteristics and electrophoretic properties of the purified enzyme indicated that it was composed of a single subunit of mol. wt. 85 000. The purified HSV-2 enzyme was used as an immunogen to prime BALB/c mice which were used to prepare monoclonal antibodies. Three monoclonal antibodies were shown by several criteria to react with the enzyme. Thus, we were able to confirm that the 85K polypeptide did indeed have nuclease activity. This polypeptide was designated ICSP 22 in earlier studies and is a major polypeptide of virus-infected cells.
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Littler E, Purifoy D, Minson A, Powell KL. Herpes simplex virus non-structural proteins. III. Function of the major DNA-binding protein. J Gen Virol 1983; 64:983-95. [PMID: 6302216 DOI: 10.1099/0022-1317-64-5-983] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The herpes simplex virus type 2 major DNA-binding protein has been functionally characterized using temperature-sensitive mutants in the complementation group 2-2. The mutants were shown to be defective in the DNA-binding protein gene by mapping the mutants to the area of the genome known to code for the protein, and by demonstrating alterations in the major DNA-binding protein induced in mutant-infected cells. The mutants were shown to be defective in the replication of virus DNA. The nature of this defect was examined by studying virus DNA synthesis in vitro and by the examination of virus enzymes. An effect of mutation in the DNA-binding protein was to destabilize both the DNA polymerase and the alkaline exonuclease.
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Abstract
The herpes simplex virus alpha, or immediate early, protein ICP4 has been shown to be central to the control of the early stages of virus replication. The detailed mechanism of this control is unknown. In this communication we show that purified ICP4 was unable to bind to DNA even though the protein was capable of such activity in a crude extract. Addition of either infected- or uninfected-cell extracts to the purified protein restored its DNA-binding activity. These results suggest that ICP4 binds to DNA only via a component of uninfected cells.
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