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D M Meredith

Publications and source records attributed to D M Meredith.

42 records · Page 3Linked to original sources

Antigenic and protein sequence homology between VP13/14, a herpes simplex virus type 1 tegument protein, and gp10, a glycoprotein of equine herpesvirus 1 and 4.

Monospecific polyclonal antisera raised against VP13/14, a major tegument protein of herpes simplex virus type 1 cross-reacted with structural equine herpesvirus 1 and 4 proteins of Mr 120,000 and 123,000, respectively; these proteins are identical in molecular weight to the corresponding glycoprotein 10 (gp10) of each virus. Using a combination of immune precipitation and Western immunoblotting techniques, we confirmed that anti-VP13/14 and a monoclonal antibody to gp10 reacted with the same protein. Sequence analysis of a lambda gt11 insert of equine herpesvirus 1 gp10 identified an open reading frame in equine herpesvirus 4 with which it showed strong homology; this open reading frame also shared homology with gene UL47 of herpes simplex virus type 1 and gene 11 of varicella-zoster virus. This showed that, in addition to immunological cross-reactivity, VP13/14 and gp10 have protein sequence homology; it also allowed identification of VP13/14 as the gene product of UL47.

Amino Acid Sequence↗

Location of open reading frames coding for equine herpesvirus type-1 glycoproteins with homology to gE and gI of herpes simplex virus.

The DNA fragments representing the entire short unique region and part of the repeat sequences of the equine herpesvirus type-1 genome were cloned into plasmid vectors. The approximate positions of the junctions between the short unique region and the inverted repeats were then located by restriction endonuclease mapping. Two open reading frames coding for potential glycoproteins have been identified within the short unique region, using DNA sequence analysis. The predicted amino acid sequences of these open reading frames had extensive homology to the herpes simplex virus glycoproteins gE and gI and the related glycoproteins of pseudorabies virus and varicella-zoster virus.

Amino Acid Sequence↗

Characterization of the high Mr glycoprotein (gP300) of equine herpesvirus type 1 as a novel glycoprotein with extensive O-linked carbohydrate.

The high Mr glycoprotein (gp300) of equine herpesvirus type 1 was found to have an Mr, estimated by SDS-PAGE, of over 400,000 and was confirmed as being a surface glycoprotein by 125I-labelling. In contrast to [3H]glucosamine, gp300 showed very low levels of [3H]glucosamine, gp300 showed very low levels of [3H]mannose incorporation. The Mr of gp300 showed no detectable change upon treatment of purified virus with N-glycanase, and showed only a small change in virus-infected cells treated with tunicamycin. In addition, gp300 failed to bind the lectin concanavalin A. Taken together, these results indicate a lack of N-linked carbohydrate on gp300. The major carbohydrate species were found to be composed primarily of O-linked chains, as indicated by the sensitivity of the protein to monensin, to exoglycanase enzymes specific for sugars present in O-linked chains and to mild alkaline borohydride treatment, which revealed three species of carbohydrate of Mr of greater than 10,000, 2400 and 1100, respectively. Neuraminidase treatment and binding of Helix pomatia lectin indicated the presence of alpha-N-acetylglucosamine and sialic acid as terminal sugars. Immunological cross-reactivity of gp300 with a high Mr protein of equine herpesvirus type 4 was shown and it also exhibited a marked Mr variation in the vaccine strain Rhinomune.

Amidohydrolases↗

Identification of the gB homologues of equine herpesvirus types 1 and 4 as disulphide-linked heterodimers and their characterization using monoclonal antibodies.

Equine herpesvirus types 1 and 4 (EHV-1 and EHV-4) labelled with [14C]glucosamine were purified from infected cell culture medium and profiles of their structural proteins were obtained that enabled identification of the major glycoproteins. Nine glycosylated polypeptides were identified for each virus. Preparations of the purified viruses each contained a glycoprotein which was linked by disulphide bonds, as determined by diagonal gel electrophoresis under reducing/non-reducing conditions. High Mr forms of this glycoprotein were detected for EHV-1 when the sample was not heated. The EHV-1 protein consisted of three polypeptides of Mr 108K, 76K and 58K and the EHV-4 protein consisted of three polypeptides of Mr 112K, 74K and 61K. Western blotting and immunoprecipitation with monoclonal antibodies confirmed that the EHV-1 gB homologue migrates with an apparent Mr of 108K (140K under non-reducing conditions) but is cleaved to give glycoproteins of 76K and 58K which are held together by disulphide bonds. The EHV-4 gB homologue consists of a 112K glycoprotein which is cleaved to give glycoproteins of 74K and 61K which are also linked by disulphide bonds.

Animals↗

Possible molecular basis for antiviral activity of certain 5-substituted deoxyuridines.

The antiviral activity of five structurally related pyrimidine nucleosides, E-5-propenyl-2'-deoxyuridine, 5-allyl-2'-deoxyuridine, E-5-(1-butenyl)-2'-deoxyuridine, 5-(2-butenyl)-2'-deoxyuridine, and 5-butyl-2'-deoxyuridine, in cell culture against herpes simplex virus type 1 was examined. Analogs in which the C-C double bond of the 5-substituent was in conjugation with the pyrimidine ring were more potent antiviral drugs than were the corresponding nonconjugated and alkyl-substituted analogs. Differences in antiviral activity similar to those observed in cell culture occurred in virus-infected mice. The molecular basis for the greater antiviral activity of the conjugated isomers was investigated. It was observed that the conjugated isomer E-5-propenyl-2'-deoxyuridine had a greater affinity for virus thymidine kinase and, as the 5'-triphosphate, for virus DNA polymerase than did the nonconjugated isomer 5-allyl-2'-deoxyuridine. The results are discussed in relation to other data in the literature.

Animals↗