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V C Bond

Publications and source records attributed to V C Bond.

23 records · Page 2Linked to original sources
PubMed1987

Poly-L-ornithine-mediated transformation of mammalian cells.

Poly-L-ornithine has been used to introduce DNA and RNA into mammalian cells in culture. Ornithine-mediated DNA transfer has several interesting and potentially useful properties. The procedure is technically straightforward and is easily applied to either small or large numbers of recipient cells. The efficiency of transformation is high. Under optimal conditions, 1 to 2% of recipient mouse L cells take up and continue to express selectable marker genes. DNA content of transformants can be varied reproducibly, yielding cells with just one or two copies of the new gene under one set of conditions, while under a different set of conditions 25 to 50 copies are acquired. Cotransformation and expression of physically unlinked genes occur at high efficiency under conditions favoring multiple-copy transfer. Polyornithine promotes gene transfer into cell lines other than L cells. These include Friend erythroleukemia cells and NIH 3T3 cells. Both are transformed about 1 order of magnitude more efficiently by this procedure than by standard calcium phosphate products. However, the method does not abolish the large transformation efficiency differences between these cell lines that have been observed previously by other techniques. (vi) mRNA synthesized in vitro was also introduced into cells by this method. The RNA was translated resulting in a transient accumulation of the protein product.

Adenine Phosphoribosyltransferase↗
PubMed1984

Fine structure physical map locations of alterations that affect cell fusion in herpes simplex virus type 1.

Fine structure physical map locations were determined for syncytial mutants (MP, syn-20, syn-102, syn-103, and syn-105) of Herpes Simplex Virus type 1 (HSV-1). All except MP were derived from the KOS strain. MP contains multiple mutations, including one that leads to the loss of accumulation of glycoprotein gC (Ruyechan et al., J. Virol. 29, 677-697, 1979). Overlapping DNA subclones within the prototypic map coordinates 0.707 to 0.810 were constructed from a library of KOS fragments. These were used along with intact mutant DNA to rescue the syn marker. Mutations in all of the mutants were rescued by KOS DNA sequences between 0.732 and 0.745. This cell-dependent syn mutation is the only lesion in the KOS-derived mutants. A second syn mutation in MP was mapped at coordinates 0.745 to 0.753. This lesion produces less fusion and is also cell-type dependent for the fusion phenotype. Cell-type independent fusion requires the presence of both mutations. The locus determining glycoprotein C (gC) production in strain MP was also mapped, using indirect immunofluorescence, to coordinates 0.745 to 0.753. Nucleotide sequences for ICP-27, an immediate early or alpha protein of unknown function, are within these coordinates. Since gC production and the syn phenotype are separable by recombination, they must be caused by independent mutations.

Animals↗
PubMed1982

The isolation and characterization of mutants of herpes simplex virus type 1 that induce cell fusion.

Six cell fusion-causing syn mutants were isolated from the KOS (syn-101 to syn-106) and three from the HFEM (syn-109) strains of herpes simplex virus type 1 (HSV-1). The mutants were studied by complementation and recombination with syn-20 (a syncytial mutant of KOS) and ts-B5 (a syncytial mutant of HFEM). Some studies also employed MP, a syncytium-inducing strain isolated from the non-syncytial parent, mP. Complementation and recombination of syn-20 and ts-B5 indicated that these two mutants were altered in two different virus genes. The recombination frequency between syn-20 and ts-B5 was very similar to that observed between MP and ts-B5, indicating the syn-20 and MP may represent alterations in the same virus gene. syn-101, syn-103, syn-104 and syn-105 were tentatively assigned to the syn-20 complementation group, while syn-107 and syn-109 were tentatively assigned to the ts-B5 complementation group, syn-106 and syn-108 were excluded from the ts-B5 group. syn-102 could not be excluded from either complementation group. syn-101 induced markedly less fusion at 38 degrees C relative to 34 degrees C. At 34 degrees C the patterns of syn-101-infected cell peptides and glycopeptides, examined by SDS-gel electrophoresis, were normal, but at 38 degrees C the amount of glycopeptide gC was particularly reduced. syn-102 produced decreased amounts of glycoproteins, and a non-glycosylated peptide, probably ICP6, was absent from extracts infected with syn-106.

Cell Fusion↗
PubMed1975

Kinetics of cell fusion induced by a syncytia-producing mutant of herpes simplex virus type I.

We have isolated a number of plaque-morphology mutants from a strain of herpes simplex virus type I which, unlike the wild type, cause extensive cell fusion during a productive viral infection. After the onset of fusion, there is an exponential decrease in the number of single cells as a function of time after infection. At a multiplicity of infection (MOI) of 3.8 plaque-forming units per cell, fusion begins 5.3 h after infection with the number of single cells decreasing to 10% of the original number 10.2 h after infection. As the MOI is gradually increased from 0.4 to 8, the onset of fusion occurs earlier during infection. However, when the MOI is increased from 8 to 86, the onset of fusion does not occur any earlier. The rate of fusion is independent of the MOI for an MOI greater than 1. The rate of fusion varies linearly with initial cell density up to 3.5 X 10(4) cells/cm2 and is independent of initial cell density at higher cell concentrations. To assay cell fusion we have developed a smiple quantitative assay using a Coulter counter to measure the number of single cells as a function of time after infection. Data obtained using a Coulter counter are similar to those obtained with a microscope assay.

Cell Count↗