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Biomedical subjects

V Mautner

Publications and source records attributed to V Mautner.

At least 55 records · Page 3Linked to original sources
PubMed1987

An adenovirus type 3 host range variant with mutations in the E1a and E3 early gene regions.

A spontaneous variant of adenovirus (Ad) type 3 (subgroup B) was identified, which did not grow in HeLa cells, but grew in 293 cells with a large plaque morphology. The variant (Ad3var100) had a defect in the the early gene region E1a; it could grow in cells that supplied E1a functions and was complemented for growth in HeLa cells by Ad5 wild-type (subgroup C) but not by the E1a deletion mutant Ad5d1312. It also bore a deletion of some 1.5 kb in the E3 region. The loss of these sequences conferred on the variant the ability to inhibit Ad5 wild-type virus, although Ad3 wild-type was dominant over the variant. No transdominance was seen between wild-type Ad3 and Ad5. The E1a mutation was placed in a wild-type background and this E1a mutant had the host range properties of the variant, but did not retain the large plaque morphology and was not dominant over Ad5. The E3 mutation was separated from the E1a lesion by marker rescue; the resulting E3 mutant retained dominance over Ad5, grew in HeLa cells and had a plaque morphology intermediate between wild-type and variant.

Adenovirus Early Proteins↗
PubMed1986

Genome analysis of species 3 adenoviruses isolated during summer outbreaks of conjunctivitis and pharyngoconjunctival fever in the Glasgow and London areas in 1981.

Genome analysis was performed on 125 adenovirus isolates from conjunctival swabs of patients with conjunctivitis obtained in Glasgow between 1981 and 1984. A summer outbreak in 1981 was mainly due to species 3 adenoviruses, of which genotype 3GB and five different genotypic variants cocirculated. Three species 3 variants were also observed in 1982. The genome changes of variants were located on physical maps of the Ad3 reference strain and found to be clustered near the ends of the adenovirus DNA (including the fiber area), whereas the hexon coding region was unaltered. In contrast to the genome heterogeneity observed among the species 3 adenoviruses collected in Glasgow in 1981 it was found that all 69 Ad3 isolates obtained from an outbreak of pharyngoconjunctival fever in a boarding school near London during the summer of 1981 possessed the 3GB genotype.

Adenoviridae Infections↗
PubMed1984

Adenovirus hexon. Sequence comparison of subgroup C serotypes 2 and 5.

The group C adenoviruses type 2 (Ad2) and type 5 (Ad5) are distinguished serologically by the antigenic determinants of the hexon and fiber capsomers . The hexon-coding region of the viral genome (map units 51.6-59.7) can be divided into three major zones with regard to DNA sequence homology between Ad2 and Ad5 on the basis of fine structure disclosed by restriction endonuclease site mapping ( Boursnell , M.E.G., and Mautner , V. (1981) Virology 112, 198-209). At the NH2-terminal end, there is almost complete restriction enzyme site homology between Ad2 and Ad5, the COOH terminus displays partial homology, and a central zone (map units 52.7-56.0) is heterologous and has no common restriction sites. We report here the DNA sequence of the Ad5 hexon gene (map units 51.6-59.7). This sequence is compared to that established for Ad2 (G. Akusj arvi , P. Alestr öm, M. Pettersson , H. Jornvall , and U. Pettersson , manuscript submitted for publication), and the heterologous zone is shown to encode an amino acid sequence that differs from that of Ad2 at many different loci within the zone (map units 52.7-56.0), interspersed with short stretches of highly conserved sequence.

Adenoviruses, Human↗
PubMed1984

Recombination in adenovirus: analysis of crossover sites in intertypic overlap recombinants.

Overlap recombination has been used as a means of generating intertypic recombinants with crossover sites located within a defined region of the adenovirus genome. Using terminal DNA fragments of adenovirus type 2 and type 5 that overlap within the vicinity of the hexon coding region (51.6-59.7 map units), two different crosses could be studied; in one the overlap entirely encompasses the hexon and there are homologous regions at either side of the overlap where recombination is expected, and in the other only one side of the overlap is capable of sustaining recombination. The overall distribution of crossover sites within the overlap has been determined by restriction endonuclease mapping, and analysed in terms of the extent of homology between Ad2 and Ad5 in this region as defined by the DNA sequences (R. Kinloch, N. Mackay, and V. Mautner (1984). J. Biol. Chem., 259, 6431-6436; G. Akusjärvi, P. Aleström, M. Pettersson, M. Lager, H. Jörnvall, and U. Pettersson (1984). Submitted). Crossovers are found only in regions of relatively high DNA homology, as previously shown for intertypic recombination between temperature-sensitive viruses (M. E. G. Boursnell and V. Mautner (1981). Virology 112, 198-209). The presence of a free DNA end within the heterologous zone is insufficient to overcome the barrier to recombination. In crosses where recombination is confined to a relatively small homologous zone (45.9-53.0 mu) there is no special distribution of crossovers within the interval; no "hot spot" is discernible at the free DNA end, suggesting that a free DNA end is not especially recombinogenic, nor at the junction between the homologous and heterologous zones, suggesting that branch migration up to the heterology does not always occur. A cross designed to furnish evidence for gene conversion gave rise to a "conventional" recombinant with a crossover located within a 21-nucleotide tract of homology.

Adenoviruses, Human↗
PubMed1983

Recombination in adenovirus: DNA sequence analysis of crossover sites in intertypic recombinants.

The nucleotide sequence of the adenovirus type 5 genome has been determined for a 620-bp region that spans the C terminus of the pVI gene and the N terminus of the hexon gene, and compared to the adenovirus type 2 DNA sequence: 25 base changes have been identified, most of which do not lead to alterations in the amino acid sequence and regulatory signals in the region. Crossover sites in three intertypic recombinants have been previously located in this region of the genome by fine restriction mapping. A sequence determination for the three recombinants, and the four ts mutants used in generating the ts+ recombinants, was carried out. The crossovers were in each case located in a small region of complete sequence homology (from 45 to 156 nucleotides long) flanked on either side by sequences derived from each parent. These structures are compatible with a reciprocal crossing over model of generalised recombination, where a recombinant joint has resolved in a region of high DNA homology. For the recombinants considered here, this region abutts onto a neighbouring region of much lower sequence homology, and it is possible that the position of the crossover is determined at least in part by the termination of branch migration at a heterologous boundary.

Adenoviruses, Human↗
PubMed1981

In vitro construction of a recombinant adenovirus Ad2:Ad5.

A hybrid virus containing the left half of the Ad5 genome and the right half of the Ad2 genome has been constructed by ligating together in vitro the BamHI-A fragment of Ad5 (map co-ordinates 0-59.5) to the BamHI-A fragment of Ad2 (map co-ordinates 59.5-100), and using this DNA to transfect susceptible cells. Viable progeny virus has been obtained which grows as well as the parental virus without any requirement for helper virus, and probably contains a hybrid hexon polypeptide consisting of the major part of the Ad5 hexon with an Ad2 carboxy terminus.

Adenoviruses, Human↗
PubMed1977

Restoration of normal morphology, adhesion and cytoskeleton in transformed cells by addition of a transformation-sensitive surface protein.

Transformed cells lack a large, external, transformation-sensitive (LETS) glycoprotein which is a major surface component of their normal counterparts. Addition of LETS glycoprotein isolated from normal cells to transfomed cells restores certain morphological features and adhesive properties characteristic of normal cells. LETS protein is detected on the cell surface both by iodination using lactoperoxidase and by immunofluorescent staining. The surface distribution pattern detected by immunofluorescence is strikingly similar to that of normal cells. After addition of LETS protein, transformed cells also exhibit well defined actin cables which are not seen in untreated, transformed cells. All these alterations can be blocked by treating LETS protein with specific antisera or by subjecting it to mild trypsinization prior to addition to transformed cells. The effects are rapidly reversible by mild trypsinization, which removes the added LETS protein. The high rate of uptake of 2-deoxyglucose, characteristic of transformed cells, is not affected by LETS protein. These results suggest that LETS protein may have a role in cell attachment and spreading, and affect the organization of cytoskeleton.

Actins↗
PubMed1977

Surface distribution of LETS protein in relation to the cytoskeleton of normal and transformed cells.

The organization of LETS protein on the surface of NIL8 hamster cells has been examined by immunofluorescence staining. The distribution of LETS protein was found to depend on the culture conditions; in subconfluent, low-serum arrested cultures the LETS protein is predominantly located at the cell-substrate interface and also in regions of cell-cell contact, whereas in dense cultures the cells are surrounded by a network of LETS protein fibrils. Transformed derivatives of these cells exhibit only sporadic staining for LETS protein, in the form of short intercellular bridges. Agents that cause alterations in cell shape and cytoplasmic filaments have been used to explore the relationship of LETS protein to the internal cytoskeletal elements. Reciprocally, perturbations of the cell surface were examined for their effects on internal filaments. The arrangement of microtubules seems to be unrelated to the presence of LETS protein in the cells studied. Actin microfilament bundles and LETS protein respond in a coordinate fashion to some perturbants but independently with respect to others. The patterns of staining for LETS protein are consistent with an involvement in cell-to-cell and cell-to-substrate adhesion.

Actins↗
PubMed1976

Interactions of KB-cell glycoproteins with an adenovirus capsid protein.

Glycoprotein material extracted from human KB cells with a flurocarbon, trichlorotrifluoroethane (Arklone P), into a waste-soluble fraction binds to fibre, a structural protein of the adenovirus type-5 capsid. The fibre-binding glycoprotein(s) were purified by ion-exchange chromatography on DEAE-Sephadex and affinity chromatography on a fibre-Sepharose support. The purification procedure also includes a trypsinization step which eliminates the bulk of contaminating KB cell proteins present in the aqueous fraction without appreciably affecting the activity of the fibre-binding glycoprotein(s). Some comparison is made of the membrane-bound receptors for adenovirus and the water-soluble fibre-binding glycoprotein(s).

Adenoviridae↗
PubMed1976

Antigenic determinants of adenovirus capsids. I. Measurement of antibody cross-reactivity.

Evidence is presented that the type-specific antibody to the adenovirus hexon is not simply the antibody with the highest activity for cross-reactive determinants, but is a distinct, minority population that recognizes seperate determinants. To quantify it, we have developed an inhibition method with radio-immunoprecipitation (RIP) as a sensitive assay for the type-specific antibody that remains after all the excess of cross-reactive antibody has been blocked by heterologous antigen. During the primary response, 0.1 to 1% of antibody to types 2 or 5 hexon is type-specific, but after boosting, this population may reach 10 to 20%. Antibody to fiber is more than 70% type-specific during primary and secondary responses. The cross-reacting antibody can be removed on immunoabsorbent columns without affecting the virus neutralization titer of the serum.

Adenoviridae↗
PubMed1976

Antigenic determinants of adenovirus capsids. II. Homogeneity of hexons, and accessibility of their determinants, in the virion.

We have tested the two principal theories which explain the previous finding that small amounts of type-specific antibody to the adenovirus hexon can neutralize infectivity, whereas even large amounts of cross-reactive antibody do not. a) It has been suggested that the type-specific determinants are especially prominent in the virion. We have therefore measured the capacity of whole virus to bind appropriate antibodies, using a sensitive radioimmunoprecipitation (RIP) system. In fact, virions bound type-specific and cross-reactive antibodies impartially. Moreover, they bound both much less effectively than did free hexon or disrupted virus, suggesting that many of each kind of determinant are inaccessible in virions. b) It has been suggested that the type-specific determinants are confined to those hexons located next to the pentons, and that they are the targets for neutralizing antibody. We have therefore studied the antigenicity of peripentonal and nonamer hexons isolated from virions, and found that each possessed both kinds of determinants. Furthermore, these were present in the same proportion as in hexons purified from the soluble antigens in infected cells ("free hexons"). We concluded that the mechanism of neutralization by antibody is complicated, and that the type-specific determinants exposed on the virion must play a crucial role.

Adenoviridae↗
PubMed1976

Spatial organization at the cell surface.

Approaches are described for analysis of spatial organization of cell surface structure. Extraction of cells with nonionic and ionic detergents, chelating and chaotropic agents, salts, and reducing agents results in selective solubilization of surface proteins. Bisimidate disulfide-containing crosslinking reagents produce complexes containing surface proteins which can be analyzed by subsequent dissociation of the complexes. Disulfide-bonded complexes are also found without addition of crosslinkers, and reducing agents aid in extracting surface proteins. These results suggest a possible role for disulfide bonds in cell surface organization. Immunofluorescent staining of cells with antisera to LETS protein and to actin reveals fibrillar structures which survive NP40 extraction. These results indicate a complex organization at the cell surface which is amenable to analysis by permutations of the methods described.

Animals↗
PubMed1975

The location of the genes coding for hexon and fiber proteins in adenovirus DNA.

A serological analysis has been made of the capsid antigens hexon and fiber from 17 Ad5-Ad2+ND1 recombinants that enables us to determine the phenotype of the recombinants. By correlation of this data with the genetic and physical maps of the adenovirus genome, obtained by recombination and restriction endonuclease analysis, the genes coding for the hexon and fiber have been assigned to specific locations on the adenovirus DNA.

Adenoviridae↗