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Watanabe M, Hirano A, Stenglein S, Nelson J, Thomas G, Wong TC. Engineered serine protease inhibitor prevents furin-catalyzed activation of the fusion glycoprotein and production of infectious measles virus. J Virol 1995; 69:3206-10. [PMID: 7707552 PMCID: PMC189026 DOI: 10.1128/jvi.69.5.3206-3210.1995] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We have identified the major cellular endoprotease that activates the fusion (F) glycoprotein of measles virus (MV) and have engineered a serine protease inhibitor (serpin) to target the endoprotease and inhibit the production of infectious MV. The F-protein precursor of MV was not cleaved efficiently into the mature F protein in human colon carcinoma cells lacking functional furin, indicating that furin is the major enzyme responsible for activation of the MV F protein. A human serpin alpha 1-antitrypsin variant was engineered to specifically inhibit furin. When expressed from a recombinant vaccinia virus in primate cells infected by MV, the engineered serpin (alpha 1-PDX) specifically inhibited furin-catalyzed cleavage of the F-protein precursor without affecting synthesis of other MV proteins. We generated human glioma cells stably expressing alpha 1-PDX. MV infection in these cells did not result in syncytia. The infected cells produced all the MV proteins, but the F-protein precursor remained largely uncleaved. This did not prevent virus assembly. However, the released virions contained inactive F-protein precursor rather than mature F protein, and infectious-virus titers were reduced by 3 to 4 orders of magnitude. These results show that a mature F protein is not required for the assembly of MV but is crucial for virus infectivity. The engineered serpin may offer a novel molecular antiviral approach against MV.
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Wong TC, Franklin C. Breach of contract. ACADEMIC MEDICINE : JOURNAL OF THE ASSOCIATION OF AMERICAN MEDICAL COLLEGES 1995; 70:90-92. [PMID: 7865059 DOI: 10.1097/00001888-199502000-00009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Zhang M, Quinn TP, Wong TC. Solution conformation of a cyclic neurokinin antagonist: a NMR and molecular dynamics study. Biopolymers 1994; 34:1165-73. [PMID: 7948730 DOI: 10.1002/bip.360340906] [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: 01/28/2023]
Abstract
The solution structure of a hexapeptide, cyclo (Gln-Trp-Phe-Gly-Leu-Met), which is a selective NK-2 antagonist, has been studied by a combination of two-dimensional nmr and molecular dynamics (MD) techniques. The simulation based on nmr and MD data resulted in the convergence to a family of structures. Free molecular dynamics for 50 ps in the presence of DMSO solvent molecules shows that the structure is energetically stable. One intramolecular hydrogen bond between the amide proton of Gln and the carbonyl oxygen of Gly was revealed. This result is consistent with the results from the measurement of the temperature coefficient of the amide protons. The extent of intermolecular hydrogen bonding between the amide protons of the peptide and DMSO was also revealed by the free MD simulation. The resulting structure of the cyclic peptide contains a variation type I' beta-turn in the Gly-Leu-Met-Gln segment. Comparison of the structure of this peptide with that of other NK-2 antagonist cyclic hexapeptides was made, and the activity of cyclic antagonists appears to be inversely related to the conformational rigidity of the cyclic peptides.
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Puri R, Wong TC, Puri RK. 1H- and 13C-nmr assignments and structural determination of a novel glycoalkaloid from Solanum platanifolium. JOURNAL OF NATURAL PRODUCTS 1994; 57:587-596. [PMID: 8064291 DOI: 10.1021/np50107a004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Four steroidal glycoalkaloids, solasonine [2], solamargine [3], khasianine [4], and ravifoline [5], with solasodine [1] as the aglycone moiety, have been isolated from Solanum platanifolium. The present study involved the characterization of the novel compound 5 by one- and two-dimensional nmr techniques and has also led to the unambiguous and total 13C- and 1H-nmr assignments of all of these steroidal glycoalkaloids and the direct elucidation of their glycosidic linkages.
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Zhang M, Wong TC. Solution conformation study of substance P methyl ester and [Nle10]-neurokinin A (4-10) by NMR spectroscopy. Biopolymers 1993; 33:1901-8. [PMID: 7505636 DOI: 10.1002/bip.360331215] [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: 01/25/2023]
Abstract
High-resolution proton spectra at 500 MHz of two tachykinin peptides, substance P methyl ester (SPOMe) and [Nle10]-neurokinin A (4-10), have been obtained in dimethylsulfoxide (DMSO), and for SPOMe, also in 2,2,2-trifluoroethanol (TFE)/water mixtures. Complete chemical shift assignments for these peptides were made based on two-dimensional (2D) nmr techniques, correlated spectroscopy and total COSY. J coupling measurement and nuclear Overhauser effect spectroscopy (NOESY) were then used to determine the conformation of these peptides in the various solvents. Based on the J coupling, NOE correlations, and temperature coefficients of the NH resonances, it is concluded that these two peptides exist in DMSO at room temperature as a mixture of conformers that are primarily extended. For SPOMe in TFE/water with high TFE content, however, helical structures are found to be present, and they become quite clear at temperatures between 270 and 280 K. The variation of the 13C chemical shifts of the C alpha (the secondary shift) with TFE contents corroborates this conclusion. The NOE and C alpha shifts show that the main helical region for SPOMe lies between 4P and 9G. The C-terminus segment L-M-NH2 is found to be quite flexible, which appears to be quite common for neurokinin-1 selective peptides.
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Abstract
We have obtained a polyclonal antiserum, N-BE, against the denatured, amino-terminal half of the measles virus (MV) nucleocapsid (N) protein and a monoclonal antibody (MAb), N46, which recognizes a conformation-dependent epitope in the same region. Amino acid residues 23 to 239 were required and sufficient for the formation of the conformational epitope. Using these antibodies, we show that the N protein of MV is synthesized as a relatively unfolded protein which first appears in the free-protein pool. This nascent N protein undergoes a conformational change into a more folded mature form. This change does not require the participation of other viral proteins or genomic RNA. The mature N protein does not accumulate in the free-protein pool but is quickly and selectively incorporated into the viral nucleocapsids. The mature N protein is a target for interaction with the phosphoprotein (P protein) of MV. This interaction interferes with the recognition of the N protein by the N46 MAb. This suggests that the association with the P protein may mask the binding site for the N46 MAb or that it induces a conformational change in the N protein.
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Hirano A, Ayata M, Wang AH, Wong TC. Functional analysis of matrix proteins expressed from cloned genes of measles virus variants that cause subacute sclerosing panencephalitis reveals a common defect in nucleocapsid binding. J Virol 1993; 67:1848-53. [PMID: 8445713 PMCID: PMC240246 DOI: 10.1128/jvi.67.4.1848-1853.1993] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We have developed an in vitro nucleocapsid-binding assay for studying the function of the matrix (M) protein of measles virus (MV) (A. Hirano, A. H. Wang, A. F. Gombart, and T. C. Wong, Proc. Natl. Acad. Sci. USA, 89:8745-8749, 1992). In this communication we show that the M proteins of three MV strains that cause acute infection (Nagahata, Edmonston, and YN) bind efficiently to the viral nucleocapsids whereas the M proteins of four MV strains isolated from patients with subacute sclerosing panencephalitis (SSPE) (Biken, IP-3, Niigata, and Yamagata) fail to bind to the viral nucleocapsids. MV Biken (an SSPE-related virus) produces variant M sequences which encode two antigenically distinct forms of M protein. A serine-versus-leucine difference is responsible for the antigenic variation. MV IP-3 (an SSPE-related virus) also produces variant M sequences, some of which have been postulated to encode a functional M protein responsible for the production of an infectious revertant virus. However, the variant M proteins of Biken and IP-3 strains show no nucleocapsid-binding activity. These results demonstrate that the nucleocapsid-binding function is conserved in the M proteins of MV strains that cause acute infection and that the M proteins of MV strains that cause SSPE exhibit a common defect in this function. Analysis of chimeric M proteins indicates that mutations in the amino-terminal, carboxy-proximal, or carboxy-terminal region of the M protein all abrogate nucleocapsid binding, suggesting that the M protein conformation is important for interaction with the viral nucleocapsid.
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Wong TC, Lee CM, Guo W, Chang DK. Conformational study of two substance P hexapeptides by two-dimensional NMR. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1993; 41:185-95. [PMID: 7681425 DOI: 10.1111/j.1399-3011.1993.tb00130.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The conformation of two substance P (SP) related hexapeptides. Glp-Phe-Phe-(L-Pro)-Leu-Met.NH2 (I) and Glp-Phe-Phe-(D-Pro)-Leu-Met.NH2 (II), in two solvents, chloroform-d and trifluoroethanol(TFE)-d3/H2O, was studied by two-dimensional NMR methods, including COSY, TOCSY, ROESY and HMQC. The study shows that these two peptides exist predominantly in the extended form in TFE/H2O, but in general exhibit a reverse-turn structure in chloroform. I is clearly less ordered than II in both solvents. Furthermore, extensive Phe3-Pro4 cis<==>trans isomerization was found in I but not in II. The differences in the conformational behavior of these two peptides, which are selective agonists for neurokinin NK1 and NK2 receptors, respectively, are discussed.
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Hirano A, Wang AH, Gombart AF, Wong TC. The matrix proteins of neurovirulent subacute sclerosing panencephalitis virus and its acute measles virus progenitor are functionally different. Proc Natl Acad Sci U S A 1992; 89:8745-9. [PMID: 1528889 PMCID: PMC49997 DOI: 10.1073/pnas.89.18.8745] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Persistence of measles virus in the brains of patients with subacute sclerosing panencephalitis (SSPE) is accompanied by changes in the viral matrix (M) protein. To understand the significance of these changes, cell culture and cell-free assays were developed to compare the functions of the M proteins of an SSPE virus Biken strain and its acute measles virus progenitor Nagahata strain. The Nagahata viral M protein is associated with the intracellular viral nucleocapsids and the plasma membrane, whereas the Biken viral M protein is localized mainly in the cytosol. The lack of M protein in the Biken viral nucleocapsids is due to a failure of the Biken M protein to bind to the viral nucleocapsids. The Biken M protein also fails to bind to the Nagahata viral nucleocapsids. Conversely, the Nagahata M protein can bind to the Biken viral nucleocapsids, although this association is not as stable at physiological salt concentration. These results offer concrete evidence that the M protein of an SSPE virus is functionally different from that of its progenitor acute measles virus.
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Gombart AF, Hirano A, Wong TC. Expression and properties of the V protein in acute measles virus and subacute sclerosing panencephalitis virus strains. Virus Res 1992; 25:63-78. [PMID: 1413994 DOI: 10.1016/0168-1702(92)90100-n] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Measles virus (MV) inserts one guanosine (G) residue at a specific site in a subpopulation of the mRNA transcribed from the phosphoprotein (P) gene to produce V mRNA. Using an antiserum against the unique carboxyl-terminal region of the predicted V protein, we found that a phosphorylated V protein was expressed in two acute MV strains (Edmonston and Nagahata) and three SSPE virus strains (Biken, Yamagata, and Niigata). The V protein of Biken strain SSPE virus was electrophoretically and antigenically indistinguishable from the V protein of Nagahata strain acute MV, the likely progenitor of the Biken strain. The V protein of these two viruses was not present in the intracellular viral nucleocapsids, but was found only in the cytosolic free protein pool. Pulse-chase experiments failed to show transport of the V protein to the plasma membrane. The V protein was also absent in the extracellular virions. The P protein synthesized from the cloned gene associated with the MV nucleocapsids in vitro, but the V protein had no affinity to the MV nucleocapsids. These results suggest that expression and properties of the V protein are conserved in chronic MV infection.
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Rataul SM, Hirano A, Wong TC. Irreversible modification of measles virus RNA in vitro by nuclear RNA-unwinding activity in human neuroblastoma cells. J Virol 1992; 66:1769-73. [PMID: 1738207 PMCID: PMC240933 DOI: 10.1128/jvi.66.3.1769-1773.1992] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The matrix (M) gene of a measles virus (MV) variant passaged in IMR-32 human neuroblastoma cells displays numerous uridine-to-cytosine transitions called biased hypermutation. Using an in vitro assay, we show that IMR-32 cells contain high levels of an activity which unwinds and irreversibly alters the base pairing of double-stranded RNA synthesized from the M gene of MV. This activity is found exclusively in the cellular nucleus and is present at a lower level in African green monkey kidney Vero cells. Experiments with mixed cell extracts suggest that the low activity in Vero cells is not due to inhibitory factors. These findings support the hypothesis that this RNA-modifying and -unwinding activity is responsible for biased hypermutation of MV strains that infect the central nervous system. Possible functions of this neural cell activity and implications for central nervous system disorders are discussed.
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Hirano A, Wong TC. Generation of mammalian cells expressing stably measles virus proteins via bicistronic RNA. J Virol Methods 1991; 33:135-47. [PMID: 1939503 DOI: 10.1016/0166-0934(91)90014-q] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The proteins of measles virus are believed to be cytotoxic, and have never been expressed stably from the cloned genes in cultured cells. We found that measles viral proteins can be expressed via a bicistronic RNA. The dominantly selectable DHFR* protein-coding region encoding a mutant dihydrofolate reductase was inserted into the 3'-untranslated regions of the measles viral genes encoding nucleoprotein (N), matrix (M) protein, and hemagglutinin (H). The tandemly arranged cistrons were placed under control by the inducible promoter of human metallothionein IIA gene, or the noninducible early promoter of simian virus 40. Upon transfecting into mammalian cells, these gene constructs synthesized bicistronic RNAs. The downstream DHFR* gene conferred resistance to methotrexate (MTX). Cells that survived MTX selection expressed stably the N, M, or H protein of measles virus. Expression of N protein was further inducible by cadmium chloride treatment. This system will be useful for studying the protein functions of measles virus, and could be applied to express other potentially toxic gene products.
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Wong TC, Ayata M, Ueda S, Hirano A. Role of biased hypermutation in evolution of subacute sclerosing panencephalitis virus from progenitor acute measles virus. J Virol 1991; 65:2191-9. [PMID: 2016756 PMCID: PMC240566 DOI: 10.1128/jvi.65.5.2191-2199.1991] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We identified an acute measles virus (Nagahata strain) closely related to a defective virus (Biken strain) isolated from a patient with subacute sclerosing panencephalitis (SSPE). The proteins of Nagahata strain measles virus are antigenically and electrophoretically similar to the proteins of Edmonston strain measles virus. However, the nucleotide sequence of the Nagahata matrix (M) gene is significantly different from the M genes of all the acute measles virus strains studied to date. The Nagahata M gene is strikingly similar to the M gene of Biken strain SSPE virus isolated several years later in the same locale. Eighty percent of the nucleotide differences between the Nagahata and Biken M genes are uridine-to-cytosine transitions known as biased hypermutation, which has been postulated to be caused by a cellular RNA-modifying activity. These biased mutations account for all but one of the numerous missense genetic changes predicted to cause amino acid substitutions. As a result, the Biken virus M protein loses conformation-specific epitopes that are conserved in the M proteins of Nagahata and Edmonston strain acute measles viruses. These conformation-specific epitopes are also absent in the cryptic M proteins encoded by the hypermutated M genes of two other defective SSPE viruses (Niigata and Yamagata strains). Nagahata-like sequences are found in the M genes of at least five other SSPE viruses isolated from three continents. These data indicate that Biken strain SSPE virus is derived from a progenitor closely resembling Nagahata strain acute measles virus and that biased hypermutation is largely responsible for the structural defects in the Biken virus M protein.
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Forsythe KL, Feather MS, Gracz H, Wong TC. Detection of Kestoses and Kestose-Related Oligosaccharides in Extracts of Festuca arundinacea, Dactylis glomerata L., and Asparagus officinalis L. Root Cultures and Invertase by C and H Nuclear Magnetic Resonance Spectroscopy. PLANT PHYSIOLOGY 1990; 92:1014-20. [PMID: 16667365 PMCID: PMC1062410 DOI: 10.1104/pp.92.4.1014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A previous study (KL Forsythe, MS Feather [1989] Carbohydr Res 185: 315-319) showed that (13)C nuclear magnetic resonance spectroscopy can be used to detect and identify mixtures of 1-kestose and neokestose after conversion to the acetate derivatives. In this study, unequivocal assignments are made for the anomeric carbon and proton signals for the above two trisaccharide acetates as well as for 6-kestose hendecaacetate and for nystose tetradecaacetate (a 1-kestose-derived tetrasaccharide). A number of oligosaccharide fractions were isolated from several plant species, converted to the acetates, and nuclear magnetic resonance spectra obtained. Using the above reference data, the following information was obtained. The trisaccharide fraction from Dactylis glomerata L. stem tissue and Asparagus officinalis L. roots contain both 1-kestose and neokestose, and the tetrasaccharide fractions contain three components, one of which is nystose. Penta- and hexasaccharide acetates were also isolated from A. officinalis L. roots and were found to contain, respectively, four and at least five components. All components of both of the above species appear to contain a kestose residue and to be produced by the sequential addition of fructofuranosyl units to these. The trisaccharide fraction from Festuca arundinacea is complex, and contains at least five different components, two of which appear to be 1-kestose and neokestose.
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Castaneda SJ, Wong TC. Leader sequence distinguishes between translatable and encapsidated measles virus RNAs. J Virol 1990; 64:222-30. [PMID: 1688383 PMCID: PMC249091 DOI: 10.1128/jvi.64.1.222-230.1990] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The 3'-terminal 55 nucleotides of the negative-strand measles virus RNA genome called the leader sequence is not transcribed into a detectable distinct RNA product. Most of the monocistronic N and bicistronic N-P RNAs lack the leader sequence. However, a subpopulation of the N and N-P RNAs and all of the antigenomes possess this leader. Here, we show that leader-containing subgenomic RNAs are functionally distinct from their leaderless counterparts. In measles virus-infected cells, leaderless monocistronic N and bicistronic N-P RNAs were associated with polysomes. By contrast, leader-containing N and N-P RNAs were found exclusively in nonpolysomal ribonucleoprotein complexes that were resistant to RNase and had a buoyant density of 1.30 g/ml, the same as that of antigenomic ribonucleoprotein complexes. Both antigenomic and subgenomic ribonucleoprotein complexes were specifically immunoprecipitated by antiserum against the N protein, and leaderless RNAs were not found in these complexes. These findings suggest that measles virus distinguishes RNAs destined for encapsidation or translation by the presence or absence of a leader sequence.
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Wong TC, Ayata M, Hirano A, Yoshikawa Y, Tsuruoka H, Yamanouchi K. Generalized and localized biased hypermutation affecting the matrix gene of a measles virus strain that causes subacute sclerosing panencephalitis. J Virol 1989; 63:5464-8. [PMID: 2585612 PMCID: PMC251217 DOI: 10.1128/jvi.63.12.5464-5468.1989] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The matrix (M) genes of Yamagata-1 strain subacute sclerosing panencephalitis virus passaged in African green monkey kidney cells and human neuroblastoma cells displayed strikingly nonrandom sequence divergence. The genes of both substrains shared a large number of uridine (U) to cytidine (C) transitions, but the latter contained numerous additional U to C changes in a localized region. Over 90% of the additional mutations were identical to the hypermutated nucleotides in the M gene found in a measles inclusion body encephalitis case. The nonrandom nature, the apparent host dependency, and the abrupt boundaries of these mutations suggest that these mutations might be caused by an extrinsic biased mutational activity rather than intrinsic polymerase errors. This mutational activity might account for the extraordinarily high C to U ratios in the non-protein-coding regions of both the M and fusion genes of wild-type measles virus.
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Hirano A, Wong TC. Mutations in 3'-untranslated region of avian sarcoma virus mutant LA46 genome confer the cis-acting temperature-sensitive replication defect. Virology 1989; 172:651-4. [PMID: 2552664 DOI: 10.1016/0042-6822(89)90209-2] [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]
Abstract
Avian sarcoma virus (ASV) PRCII mutant LA46 carried a unique cis-acting temperature sensitive (ts) defect affecting virus replication. The 3'-untranslated region of the LA46 genome contained multiple base substitutions in the direct repeat region and a long insertion. Although these sequences were not present in PRCII, most of these changes were found in various other ASVs and the long insertion shared extensive homology with the so called E region in certain ASV strains. By constructing chimeric retroviruses, the ts defect was mapped to the altered 3'-noncoding region. However, site-specific mutagenization targeted towards a four-nucleotide substitution unique to LA46 failed to implicate these mutations in the ts phenotype.
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Castaneda SJ, Wong TC. Measles virus synthesizes both leaderless and leader-containing polyadenylated RNAs in vivo. J Virol 1989; 63:2977-86. [PMID: 2470923 PMCID: PMC250852 DOI: 10.1128/jvi.63.7.2977-2986.1989] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The minus-sense RNA genome of measles virus serves as a template for synthesizing plus-sense RNAs of genomic length (antigenomes) and subgenomic length [poly(A)+ RNAs]. To elucidate how these different species are produced in vivo, RNA synthesized from the 3'-proximal N gene was characterized by Northern RNA blot and RNase protection analyses. The results showed that measles virus produced three size classes of plus-sense N-containing RNA species corresponding to monocistronic N RNA, bicistronic NP RNA, and antigenomes. Unlike vesicular stomatitis virus, measles virus does not produce a detectable free plus-sense leader RNA. Instead, although antigenomes invariably contain a leader sequence, monocistronic and bicistronic poly(A)+ N-containing RNAs are synthesized either without or with a leader sequence. We cloned and characterized a full-length cDNA representing a product of the latter type of synthesis. mRNAs and antigenomes appeared sequentially and in parallel with leaderless and leader-containing RNAs. These various RNA species accumulated concurrently throughout infection. However, cycloheximide preferentially inhibited accumulation of antigenomes and leader-containing RNA but not leaderless and subgenomic RNAs late in infection, suggesting that synthesis of the former RNA species requires a late protein function or a continuous supply of structural proteins or both. These results reveal a previously undescribed mechanism for RNA synthesis in measles virus.
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Ayata M, Hirano A, Wong TC. Structural defect linked to nonrandom mutations in the matrix gene of biken strain subacute sclerosing panencephalitis virus defined by cDNA cloning and expression of chimeric genes. J Virol 1989; 63:1162-73. [PMID: 2915379 PMCID: PMC247811 DOI: 10.1128/jvi.63.3.1162-1173.1989] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Biken strain, a nonproductive measles viruslike agent isolated from a subacute sclerosing panencephalitis (SSPE) patient, contains a posttranscriptional defect affecting matrix (M) protein. A putative M protein was translated in vitro with RNA from Biken strain-infected cells. A similar protein was detected in vivo by an antiserum against a peptide synthesized from the cloned M gene of Edmonston strain measles virus. By using a novel method, full-length cDNAs of the Biken M gene were selectively cloned. The cloned Biken M gene contained an open reading frame which encoded 8 extra carboxy-terminal amino acid residues and 20 amino acid substitutions predicted to affect both the hydrophobicity and secondary structure of the gene product. The cloned gene was expressed in vitro and in vivo into a 37,500 Mr protein electrophoretically and antigenically distinct from the M protein of Edmonston strain but identical to the M protein in Biken strain-infected cells. Chimeric M proteins synthesized in vitro and in vivo showed that the mutations in the carboxy-proximal region altered the local antigenicity and those in the amino region affected the overall protein conformation. The protein expressed from the Biken M gene was unstable in vivo. Instability was attributed to multiple mutations in both the amino and carboxy regions. A surprising number of mutations in both the coding and noncoding regions of the Biken M gene were identical to those in an independently isolated SSPE virus strain with a similar defect. These results offer insights into the basis of the defect in Biken strain and pose intriguing questions about the evolutionary origins of SSPE viruses in general.
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Lee RT, Wong TC, Lee R, Yue L, Lee YC. Efficient coupling of glycopeptides to proteins with a heterobifunctional reagent. Biochemistry 1989; 28:1856-61. [PMID: 2470404 DOI: 10.1021/bi00430a064] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A heterobifunctional linking reagent containing a masked aldehydo group and acyl hydrazide was synthesized for coupling of glycopeptides and other amino-containing compounds to proteins. After conversion to acyl azide, the reagent reacts with the amino group of a glycopeptide, and the modified glycopeptide is deacetalized with a weak acid to unmask the aldehydo group, which is then conjugated to bovine serum albumin (BSA) by reductive alkylation with pyridine-borane. The overall reaction scheme proceeds under relatively mild conditions. When the protein amino group was in a large excess (greater than 6-fold) of the aldehyde reagent, the efficiency of conjugation was as high as 88% even at submicromole levels. As a test case for application of this reagent, 6-aminohexyl beta-D-galactopyranoside (Gal-AH) was attached to the linking reagent and conjugated to BSA at various aldehyde-to-protein molar ratios ranging from 25 to 200. The level of O-galactosyl residue incorporated into BSA by this reagent far exceeded that observed in a similar reductive alkylation involving S-galactoside reagents [Lee, R. T., & Lee, Y. C. (1980) Biochemistry 19, 156-163]. By use of the present conjugating procedure, as many as 112 mol of Gal-AH residues were incorporated per mole of BSA, which represents near total modification of the amino groups. Some binding characteristics of the new BSA derivatives were studied in the mammalian hepatic galactose/N-acetylgalactosamine specific lectin system along with other types of BSA derivatives (containing S-galactosyl residues). In general, the behavior of the new derivatives was similar to that of other types. For instance, the affinity increased exponentially at low sugar substitution levels (up to 30 mol of galactosyl residues/mol of BSA), and the slope of exponential increase and affinity at a given sugar substitution level was similar to those of other types.
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Wong TC, Townsend RR, Lee YC. Synthesis of D-galactosamine derivatives and binding studies using isolated rat hepatocytes. Carbohydr Res 1987; 170:27-46. [PMID: 3435903 DOI: 10.1016/0008-6215(87)85003-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Derivatives of glycosides of D-galactosamine were prepared in order to study further the binding requirement of the Gal/GalNAc receptor in mammalian hepatocytes. These structures included N-propanoyl, N-benzoyl, and N,N-phthaloyl derivatives of 2-hydroxyethyl 2-amino-2-deoxy-beta-D-galactopyranoside, 6-amino-hex-1-yl 2-deoxy-2-(trifluoroacetamido)-beta-D-galactopyranoside, the mono- and di-O-methyl derivatives of allyl 2-acetamido-2-deoxy-beta-D-galactopyranoside, and allyl 2-acetamido-2,4-dideoxy-4-fluoro-alpha-D-galactopyranoside. The inhibition results confirmed some of our previous findings on the involvement of the hydroxyl groups, and provided new information on the involvement of the N-substituent, as well as on the requirement of hydrogen bonding of the 4-hydroxyl group in binding.
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Koch DD, Del Pero RA, Wong TC, McCulloch RR, Weaver TA. Scleral flap surgery for modification of corneal astigmatism. Am J Ophthalmol 1987; 104:259-64. [PMID: 3631184 DOI: 10.1016/0002-9394(87)90414-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We performed resections and recessions of scleral flaps on human cadaver eyes in order to measure the induced change in keratometric astigmatism. We prepared 3-mm scleral flaps that were 3, 5, 7, or 10 mm long and resected or recessed these flaps up to 1 mm in 0.25-mm increments. Scleral flap resection resulted in up to 10.1 D of net corneal steepening along the meridian of the incision. Scleral flap recessions resulted in up to 7.7 D of net corneal flattening along the meridian of the incision; the effect increased with increasing flap length in the recessed eyes. There was a tendency toward mean corneal flattening with resections and mean corneal steepening with recessions.
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73
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Wong TC, Wipf G, Hirano A. The measles virus matrix gene and gene product defined by in vitro and in vivo expression. Virology 1987; 157:497-508. [PMID: 3824908 DOI: 10.1016/0042-6822(87)90292-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Sequence analysis of full-length cDNA clones of the measles virus matrix gene revealed three possible open reading frames: M, X1, and X2. The M reading frame differed from the reported sequence by a single nucleotide corresponding to a conservative lysine to arginine amino acid substitution near the carboxy-terminus conserved among the M proteins of paramyxoviruses. The putative X reading frames contained no translational termination codon due to a frame-shift mutation. The protein-coding potential of these reading frames was examined by in vitro translation and DNA-mediated gene transfer into primate cells. The M reading frame produced a 38,000 Mr protein indistinguishable from the M protein in measles virus-infected cells. This protein was not phosphorylated nor processed post-translationally in vivo. The putative X1 and X2 reading frames could be translated into proteins when placed near the 5' terminus of the RNA. The resulting proteins were heterogeneous due to the lack of a termination codon. Translation from the putative X reading frames was adversely affected by an upstream AUG codon and these reading frames were unable to synthesize proteins in their normal 3' locations. At least 146 nucleotides of these 3'-untranslated sequences could be deleted without affecting the expression of M protein in vitro or in vivo. Thus despite the multiple open reading frames, the measles virus M gene is functionally monocistronic.
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74
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Rajasekaran K, Gnanasekaran C, Wong TC. Substituent effects on carbon-13 NMR chemical shifts of side chain carbonyl carbons of 4-substituted 1-naphthamides. J CHEM SCI 1987. [DOI: 10.1007/bf02900721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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75
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Wong TC, Hirano A. Structure and function of bicistronic RNA encoding the phosphoprotein and matrix protein of measles virus. J Virol 1987; 61:584-9. [PMID: 3027385 PMCID: PMC253984 DOI: 10.1128/jvi.61.2.584-589.1987] [Citation(s) in RCA: 34] [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
Two independent full-length replicas of a bicistronic RNA species containing the complete P and M genes of measles virus arranged in tandem were isolated from an expressible cDNA library. Sequences at the 5' and 3' termini suggested that the bicistronic RNA was initiated and terminated at precisely the same locations as the monocistronic mRNAs of the P and M genes, respectively. The P and M cistrons were fused together via an intergenic region which was exactly colinear with and complementary to the intergenic region of the genomic RNA. This RNA species was polyadenylated at the normal polyadenylation site at the 3' terminus of the M cistron, but not in the intergenic region. By DNA-mediated gene transfer, these cDNA clones were expressed into bicistronic RNA containing both P and M sequences in primate cells. RNA thus generated did not undergo nucleolytic processing but was translated into high levels of a 70,000-Mr protein immunoprecipitated by monoclonal antiserum against the measles virus P protein. M protein was not produced in the same cells even though the M cistron could direct M protein synthesis in vitro once excised from the upstream P cistron. These results suggested that bicistronic RNA could direct protein synthesis from the first but not the second cistron and might contribute at least in part to expression of viral genes in vivo.
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76
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Townsend RR, Hardy MR, Wong TC, Lee YC. Binding of N-linked bovine fetuin glycopeptides to isolated rabbit hepatocytes: Gal/GalNAc hepatic lectin discrimination between Gal beta(1,4)GlcNAc and Gal beta(1,3)GlcNAc in a triantennary structure. Biochemistry 1986; 25:5716-25. [PMID: 2430615 DOI: 10.1021/bi00367a055] [Citation(s) in RCA: 128] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Glycopeptides were isolated from bovine fetuin after digestion with Pronase, aminopeptidase M, and carboxypeptidase Y. The glycopeptides were derivatized with tert-butyloxycarbonyltyrosine and separated on the basis of peptide by using reverse-phase high-performance liquid chromatography. Using 400-MHz 1H NMR, the asialotriantennary oligosaccharides at each of the three N-linked glycosylation sites were found to be combinations of the following two structures in which the third branch is either Gal beta(1,4)GlcNAc or Gal beta(1,3)GlcNAc: (formula; see text) The asialotriantennary glycopeptides containing all beta(1,4)-lactosamine as the branches were designated Gal beta(1,4)GlcNAc-TRI while triantennary glycopeptides containing beta(1,3)-lactosamine as branch III were termed Gal beta(1,3)GlcNAc-TRI. The Gal beta(1,3)GlcNAc unit was localized predominantly to the branch III arm on the basis of a downfield shift (-0.027 ppm) in the H-1 and upfield shift (0.01 ppm) in the NAc methyl signals from the branch III GlcNAc resulting from Gal beta(1,3) instead of Gal beta(1,4) substitution. Revised assignments are proposed for the H-1's of Gal residues 6 (delta 4.464) and 8 (delta 4.471) [Vliegenthart, J. F. G., Dorland, L., & van Halbeek, H. (1983) Adv. Carbohydr. Chem. Biochem. 41, 209-373] in a Gal beta(1,4)GlcNAc-TRI. The proportion of Gal beta(1,3)GlcNAc-TRI glycopeptides from the Asn-Asp, Asn-Gly, and Asn-Cys sites was found to be 40%, 60%, and 20%, respectively. Analysis of the binding of these glycopeptides, containing from 20% to 60% Gal beta(1,3)GlcNAc as branch III, to rabbit hepatocytes revealed that the greater the proportion of Gal beta(1,3)GlcNAc, the lower the affinity of the mixture. The Kd for Gal beta(1,4)GlcNAc-TRI was found to be between 3.6 and 5.4 nM (P = 0.10) with a mean of 4.4 nM from binding data analyzed by using the LIGAND program [Munson, P. J., & Rodbard, D. (1980) Anal. Biochem. 107, 220-239] and computer simulations of the binding of two ligands as a mixture to one receptor site. The Kd of Gal beta(1,3)GlcNAc-TRI oligosaccharide, prepared by hydrazinolysis, was found to be 305 nM from inhibition studies.
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77
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Wong TC, Bard DS, Pearce LW. Unusual case of IUD-associated postabortal sepsis complicated by an infected necrotic leiomyoma, suppurative pelvic thrombophlebitis, ovarian vein thrombosis, hemoperitoneum and drug fever. THE JOURNAL OF THE ARKANSAS MEDICAL SOCIETY 1986; 83:138-47. [PMID: 2944873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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78
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79
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Wong TC, Hirano A. Functional cDNA library for efficient expression of measles virus-specific gene products in primate cells. J Virol 1986; 57:343-8. [PMID: 3753613 PMCID: PMC252733 DOI: 10.1128/jvi.57.1.343-348.1986] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
A cDNA library designed for high-level expression of measles virus-specific gene products in mammalian cells was generated. From this library, functional clones which contained the entire protein-coding sequences of the nucleocapsid (N) and the phosphoprotein (P) genes were isolated. By DNA-mediated gene transfer into a line of simian virus 40-transformed monkey kidney cells, the N-specific cDNA was expressed into a single polypeptide of about 60,000 Mr, which was immunoprecipitated by monoclonal antibodies against the measles virus N protein. In contrast, the P-specific cDNA could be expressed into either one or two species of polypeptides of 75,000 or 70,000 Mr, both of which were immunoprecipitated by monoclonal antibodies against the measles virus P protein.
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80
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81
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Kovác P, Glaudemans CP, Guo W, Wong TC. Synthesis of methyl O-(3-deoxy-3-fluoro-beta-D-galactopyranosyl)-(1----6)-O-beta-D- galactopyranosyl-(1----6)-3-deoxy-3-fluoro-beta-D-galactopyranoside and related N.M.R. studies. Carbohydr Res 1985; 140:299-311. [PMID: 4053103 DOI: 10.1016/0008-6215(85)85130-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Sequential tritylation, benzoylation, and detritylation of methyl 3-deoxy-3-fluoro-beta-D-galactopyranoside gave crystalline methyl 2,4-di-O-benzoyl-3-deoxy-3-fluoro-beta-D-galactopyranoside (9), which was used as the initial nucleophile in the synthesis of the target oligosaccharide (16). Treatment of 9 with 2,3,4-tri-O-benzoyl-6-O-bromoacetyl-alpha-D-galactopyranosyl bromide gave the corresponding disaccharide derivative 13, having a selectively removable blocking group at O-6'. Debromoacetylation of 13 afforded the disaccharide nucleophile 14 which, when treated with 2,4,6-tri-O-benzoyl-3-deoxy-3-fluoro-alpha-D-galactopyranosyl bromide, gave the fully protected trisaccharide 15. Debenzoylation of 15 gave the title glycoside 16. Condensation reactions were performed with silver trifluoromethane-sulfonate as a promoter in the presence of sym-collidine under base-deficient conditions, and gave excellent yields of the desired beta(trans)-products. Analyses of the 1H- and 13C-n.m.r. spectra, as well as determination of the JCF and JHF coupling constants, were made by using various one- and two-dimensional n.m.r. techniques.
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82
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Hirano A, Vogt PK, Wong TC. Cloned DNA of defective avian sarcoma virus mutant LA46 encodes the cis-acting temperature-sensitive defect in replication. Virology 1985; 143:684-9. [PMID: 2998036 DOI: 10.1016/0042-6822(85)90413-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Avian defective sarcoma virus mutant LA46 carries a temperature-sensitive defect in replication and transformation. To elucidate this defect, we cloned the integrated provirus of LA46. By DNA-mediated transfection, the cloned DNA induced fusiform-transformed foci in chick embryo fibroblasts without helper virus. LA46-encoded transformation-specific protein p105 was expressed in these transformants in the absence of helper virus-encoded proteins. Superinfection of the transformed cells with different helper viruses resulted in the rescue of pseudotypes. All the rescued pseudotypes retained the temperature-sensitive phenotype in virus replication and transformation, suggesting that the defect was due to a cis-acting lesion in the LA46 genome. Restriction enzyme comparison between LA46 and wild-type virus revealed sequence differences near the 5' and 3' termini of the LA46 genome, including the long terminal repeat regions.
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83
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Wong TC, Goodenow RS, Sher BT, Davidson N. The promoter of the long terminal repeat of feline leukemia virus is effective for expression of a mouse H-2 histocompatibility gene in mouse and human cells. Gene 1985; 34:27-38. [PMID: 2989102 DOI: 10.1016/0378-1119(85)90291-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
DNA-mediated gene transfer techniques have been used to study the effectiveness of a novel construction involving the feline leukemia virus long terminal repeat (FeLV LTR) for expressing the mouse H-2 Ld gene in mouse and human cells. In this construction, the transcription initiation (promoter) and termination (polyadenylation) functions of the FeLV LTR have been split by insertion of a promoterless H-2 gene between them. An S1 nuclease assay has been developed that makes it possible to measure accumulated LdRNA against a background of endogenous major histocompatibility antigen RNAs in mouse and human cells. In mouse cells, the H-2 Ld gene was expressed at approximately equal levels (measured as accumulated RNA) when driven either by its own promoter or by the FeLV LTR construction. In human cells, expression at the RNA level was highest when driven by the FeLV LTR. We conclude that the FeLV LTR construction is useful for expressing foreign genes in human cells.
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Abstract
Evidence is provided that the trisaccharide beta DGal(1----4)beta DGlcNAc(1----6)beta DGal is bound by the monoclonal anti-I Ma antibody beginning with a basically nonpolar cleft at the surface of the protein which comes into contact with a weakly polar region of the trisaccharide that extends from the C-5 methylene group of the reducing unit about the surfaces involving the acetamido grouping and the OH-3' of the beta DGlcNAc unit intramolecularly hydrogen bonded to the O-5'' of the nonreducing beta DGal unit and up to the C-5'' methylene group. The combining site then terminates with a polar grouping at its periphery which is disposed to react with OH-6'' and likely OH-4'' in a highly specific manner. The hydroxyl groups at positions 1, 2, 3, 4, 6', 3'' and 4'' remain in contact with the aq. phase. This conclusion was deduced from the relative potencies as inhibitors of a wide number of synthetic compounds that bear varying structural relationships to the trisaccharide. It appears that the stability of the complex is mainly related to attractive interactions between two large complementary and essentially hydrophobic surfaces relative to those when these surfaces are exposed to water.
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85
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Wong TC, Lai MM, Hu SS, Hirano A, Vogt PK. Class II defective avian sarcoma viruses: comparative analysis of genome structure. Virology 1982; 120:453-64. [PMID: 6285611 DOI: 10.1016/0042-6822(82)90045-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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86
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87
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Hirano A, Wong TC, Vogt PK. A temperature-sensitive lesion affecting levels of transformation-specific viral RNA in a mutant of avian sarcoma virus PRCII. Virology 1982; 116:646-9. [PMID: 6278732 DOI: 10.1016/0042-6822(82)90157-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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88
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Kabat EA, Liao J, Burzynska MH, Wong TC, Thøgersen H, Lemieux RU. Immunochemical studies on blood groups--LXIX. The conformation of the trisaccharide determinant in the combining site of anti-I Ma. Mol Immunol 1981; 18:873-81. [PMID: 6174855 DOI: 10.1016/0161-5890(81)90010-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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89
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Cohen RS, Wong TC, Lai MM. Characterization of transformation- and replication-specific sequences of reticuloendotheliosis virus. Virology 1981; 113:672-85. [PMID: 6267804 DOI: 10.1016/0042-6822(81)90196-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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90
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Wong TC, Webster JG, Montoye HJ, Washburn R. Portable accelerometer device for measuring human energy expenditure. IEEE Trans Biomed Eng 1981; 28:467-71. [PMID: 7287045 DOI: 10.1109/tbme.1981.324820] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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91
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Wong TC, Tereba A, Vogt PK, Lai MM. Characterization of the transformation-specific sequences of avian erythroblastosis virus in normal vertebrate cells. Virology 1981; 111:418-26. [PMID: 6166118 DOI: 10.1016/0042-6822(81)90345-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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92
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Wong TC, Lai MM. Avian reticuloendotheliosis virus contains a new class of oncogene of turkey origin. Virology 1981; 111:289-93. [PMID: 6263007 DOI: 10.1016/0042-6822(81)90674-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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93
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Hu SS, Lai MM, Wong TC, Cohen RS, Sevoian M. Avian reticuloendotheliosis virus: characterization of genome structure by heteroduplex mapping. J Virol 1981; 37:899-907. [PMID: 6262534 PMCID: PMC171086 DOI: 10.1128/jvi.37.3.899-907.1981] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The genome structure of defective, oncogenic avian reticuloendotheliosis virus (REV) was studied by heteroduplex mapping between the full-length complementary DNA of the helper virus REV-T1 and the 30S REV RNA. The REV genome (5.5 kilobases) had a deletion of 3.69 kilobases in the gag-pol region, confirming the genetic defectiveness of REV. In addition, REV lacked the sequences corresponding to the env gene but contained, instead, a contiguous stretch (1.6 to 1.9 kilobases) of the specific sequences presumably related to viral oncogenicity. Unlike those of other avian acute leukemia viruses, the transformation-specific sequences of REV were not contiguous with the gag-pol deletion. Thus, REV has a genome structure similar to that of a defective mink cell focus-inducing virus or a defective murine sarcoma virus. An additional class of heteroduplex molecules containing the gag-pol deletion and two other smaller deletion loops was observed. These molecules probably represented recombinants between the oncogenic REV and its helper virus.
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94
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Wong TC, Lewis RB, Bose HR, Kang CY. Assembly of avian reticuloendotheliosis virus: association of the core precursor polypeptide with the intracellular ribonucleoprotein complex. J Virol 1980; 34:484-9. [PMID: 6246276 PMCID: PMC288727 DOI: 10.1128/jvi.34.2.484-489.1980] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A virus-specific ribonucleoprotein complex is present in the cytoplasm of reticuloendotheliosis virus-transformed chicken bone marrow cells. This ribonucleoprotein complex contains viral reverse transcriptase activity and may represent a precursor to the budding virion. The major viral polypeptide associated with the ribonucleoprotein complex was a polypeptide with a molecular weight of 63,000. This protein exhibited a precursor-product relationship with the major reticuloendotheliosis virus structural core protein p29. Core polypeptides were not associated with the intracellular ribonucleoprotein complex. Thus, p29 was incorporated into the virion in the form of its precursor Pr63. The cleavage of Pr63 in the ribonucleoprotein complex was accomplished either during the budding process of shortly after the release of particles from the cell.
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95
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Wong TC, Barzilai DC, Smith RE, McConahey WM. Electrocardiographic voltage changes during hyperthyroidism. Mayo Clin Proc 1979; 54:763-8. [PMID: 159984] [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: 12/13/2022]
Abstract
Electrocardiograms of 67 thyrotoxic patients were studied. Subsequent electrocardiograms during euthyroidism in 16 patients permitted an analysis of voltage changes. Decreases in voltages after radioiodine therapy were significant (P less than 0.01) for the P wave in lead, V1, R wave in leads II, AVF, V4, V5, and V6, maximal RS wave, and maximal R wave and were present in all but one patient. Criteria for left ventricular hypertrophy (sum of S wave in V1 plus R wave in V5 or V6 greater than 35 mm), present in 21% of patients, regressed in all five patients who had later electrocardiograms during euthyroidism. Left ventricular hypertrophy or high-voltage R waves in the absence of usual causes may suggest the presence of hyperthyroidism. The concept that cardiac voltage is determined in part by thyroid hormone is reviewed; this relationship may be the basis for increased voltage in hyperthyroidism as well as decreased voltage in hypothyroidism.
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96
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Wong TC, Kang CY. Isolation and characterization of a virus-specific ribonucleoprotein complex from reticuloendotheliosis virus-transformed chicken bone marrow cells. J Virol 1978; 28:34-44. [PMID: 81319 PMCID: PMC354245 DOI: 10.1128/jvi.28.1.34-44.1978] [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: 12/12/2022] Open
Abstract
Chicken bone marrow cells transformed by reticuloendotheliosis virus (REV) produce in the cytoplasm a ribonucleoprotein (RNP) complex which has a sedimentation value of approximately 80 to 100S and a density of 1.23 g/cm3. This RNP complex is not derived from the mature virion. An endogenous RNA-directed DNA polymerase activity is associated with the RNP complex. The enzyme activity was completely neutralized by anti-REV DNA polymerase antibody but not by anti-avian myeloblastosis virus DNA polymerase antibody. The DNA product from the endogenous RNA-directed DNA polymerase reaction of the RNP complex hybridized to REV RNA but not to avian leukosis virus RNA. The RNA extracted from the RNP hybridized only to REV-specific complementary DNA synthesized from an endogenous DNA polymerase reaction of purified REV. The size of the RNA in the RNP is 30 to 35S, which represents the subunit size of the genomic RNA. No 60S mature genomic RNA was found within the RNP complex. The significance of finding the endogenous DNA polymerase activity in the viral RNP in infected cells and the maturation process of 60S virion RNA of REV are discussed.
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Wong TC, Desser SS. Leucocytozoon dubreuili: a sporozoite in a gametocyte in an erythrocyte of the avian host. J Parasitol 1977; 63:766-8. [PMID: 407350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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98
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Wong TC, Desser SS. Fine structure of oocyst transformation and the sporozoites of Leucocytozoon dubreuili. THE JOURNAL OF PROTOZOOLOGY 1976; 23:115-26. [PMID: 818366 DOI: 10.1111/j.1550-7408.1976.tb05253.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The sporogonic stages of Leucocytozoon dubreuili in the midgut and salivary glands of the simuliid vectors was studied by electron microscopy. Young uninucleate oocysts have a pellicle that initially resembles that of the ookinete. Numerous electron-dense bodies and microtubules in the peripheral cytoplasm may be involved in the formation of the cyst wall. The dense bodies appear to give rise to the amorphous material of the wall. The tubules which run circumferentially beneath the oocyst's boundary probably serve as a skeletal support for the cell surface during deposition of the wall material.
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Abstract
The morphology and development of four members of the reticuloendotheliosis virus group were studied by transmission electron microscopy. Virions of duck spleen necrosis virus, duck infectious anemia virus, chicken syncytial virus, and reticuloendotheliosis virus strain T are sperical with a diameter of approximately 110 nm. They are covered with surface projections about 6 nm long and 10 nm in diameter. The center-to-center distance of surface projections is about 14 nm. The budding virions contain crescent-shaped electron-dense cores 73 nm in diameter with electron-lucent centers. After release of the virions the cores apparently become condensed to 67 nm in diameter. Virions were found budding at the plasma membrane and into smooth-walled, intracytoplasmic vesicles of productively infected cells. The distribution of budding reticuloendotheliosis viruses on cells appeared random over the cell surface, and occasionally aberrant multiple forms of budding virions were observed. The virions appear to resemble mammalian leukemia and sarcoma viruses more closely than avian leukosis-sarcoma viruses.
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100
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Wong TC, Schulman H. Endometrial aspiration as a means of early abortion. Obstet Gynecol 1974; 44:845-52. [PMID: 4437821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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