Simplified mammalian DNA isolation procedure.
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Biomedical subjects
Publications and source records attributed to A Zijderveld.
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Coronavirus spike protein genes were expressed in vitro by using the recombinant vaccinia virus expression system. Recombinant spike proteins were expressed at the cell surface and induced cell fusion in a host-cell-dependent fashion. The intracellular transport of recombinant spike proteins was studied. The half time of acquisition of resistance to endo-beta-N-acetylglucosaminidase H was approximately 3 h for the recombinant feline infectious peritonitis virus S protein. The S protein in feline infectious peritonitis virus-infected cells was found to have a half time of acquisition of resistance to endo-beta-N-acetylglucosaminidase H of approximately 1 h. This difference can be explained by the fact that coronavirus budding takes place at intracellular membranes and that the oligosaccharides of the spike protein are modified after budding. Apparently, spike protein incorporated into budded virions is transported faster through the Golgi apparatus than is spike protein alone. These findings provide new insights into the mechanism of coronavirus budding and are discussed in relation to current models of intracellular transport and sorting of proteins.
We describe a technique for the systematic inactivation of nonessential genes within the genome of a herpesvirus without the requirement for phenotypic selection. This technique is based on the insertion of an oligonucleotide containing translational stop codons at a random site within a large cloned viral DNA fragment. Mutant virus is then reconstituted by cotransfection with overlapping viral clones, together comprising the entire viral genome, as described previously (M. van Zijl, W. Quint, J. Briaire, T. de Rover, A. Gielkens, and A. Berns, J. Virol. 62:2191-2195, 1988). This technique was used to construct, in a single experiment, a set of 13 viable pseudorabies virus strains with oligonucleotide insertions within all known genes of the Us region except for the gp50 gene, which proved essential for virus growth in cell culture. The growth rate in porcine kidney cells of mutants of all nonessential Us genes was similar to that of the parental virus, with the exception of a mutant of the recently identified protein kinase gene.