Characterization of the electrophoretic mobility mutation in the N protein of the <i>ts</i>D1 mutant of vesicular stomatitis virus New Jersey serotype

Some isolates of the temperature sensitive mutant tsD1 of complementation group D of vesicular stomatitis virus of New Jersey serotype have a nucleocapsid (N) protein which shows an increased electrophoretic mobility on sodium dodecyl sulfate –polyacrylamide gel electrophoresis (SDS–PAGE) when compared with wild type. Utilizing techniques involving specific chemical cleavage at tryptophan or methionine residues, as well as enzymatic cleavage with carboxypeptidases A and B, we have determined that residues near the carboxyterminus are responsible for the electrophoretic difference of the mutant protein. We have further shown that there are no differences in the tryptic peptides of the mutant compared with the wild type or a non-ts revertant in this region of the protein. We have identified a tryptic peptide located outside the relevant carboxyterminal region which is distinct in mutant and revertant. We conclude that the mutation producing the aberrant electrophoretic mobility of N protein of the tsD1 mutant is a missense point mutation located at least 40 amino acid residues from the carboxyterminus and which interacts with a more proximal carboxyregion so as to influence electrophoretic mobility on SDS–PAGE. </jats:p

Enhanced resolution of geological structures from magnetic data: an example from the Abitibi Greenstone Belt of Northern Ontario

Structural information about that portion of the economically important Destor–Porcupine Deformation Zone and its associated faults, which lie buried under many metres of Clay Belt sediments in the region north of Matheson, Ontario, must rely principally on interpretation of geophysical data. In this area, the Archean greenstones of the Abitibi are crosscut by at least three generations of strongly magnetic diabase dykes. The predominant dyke set, the Matachewan, trend north–south, orthogonal to structures in the greenstones. Directional horizontal derivative analysis of the total magnetic field, which has a much sharper angular cutoff than that provided by standard Fourier-based filters, provides a method for separating the magnetic contributions from these two sources. This analysis revealed the existence of a previously unidentified fault (the Winslow fault) located to the north of, and parallel to, the economically significant Pipestone Fault. We also define a second new fault, the Carr fault, that is intimately associated with the existence of a buried felsic intrusive complex in Carr Township. Possible associations between these faults and previously known faults defined from surface mapping programs are explored. </jats:p

Ribonucleic Acid Polymerase Induced in L-Cells Infected with Vesicular Stomatitis Virus

RNA polymerase activity capable of synthesizing long-chain, heteropolymeric RNA is associated with specific ribonucleoprotein complexes present in the cytoplasm of cells infected with vesicular stomatitis virus (VSV). The synthesis is independent of added exogenous template and the product labelled with GTP precursors can be totally annealed with excess virion RNA. The enzyme activity is therefore a transcriptase similar to that observed in association with the mature VSV virion. </jats:p

Foreign Gene Expression by Human Adenovirus Type 5-Based Vectors Studied Using Firefly Luciferase and Bacterial β-Galactosidase Genes as Reporters

AbstractAdenovirus (Ad) vectors have been used extensively to obtain high-level expression of foreign genes in mammalian cells and are currently being studied for use as live viral-vectored vaccines and as gene transfer vectors for gene therapy. Many Ad recombinants have been generated that express foreign genes inserted in early region 3 (E3); however, little has been done to study the importance for germ expression of regulatory sequences flanking the gene. We have generated a series of AdS helper-independent vectors that contain the firefly luciferase gene or the bacterial β-galactosidase gene (LacZ) with or without simian virus 40 (SV40) regulatory sequences, combined with E3 deletions of 1.88 or 2.69 kb. The greatest levels of luciferase expression were obtained with a vector containing the luciferase gene under the control of the SV40 promoter and polyadenylation signal inserted in a 1.88-kb E3 deletion. In contrast, LacZ expression was highest with a vector containing the LacZ gene with just the SV40 polyadenylation sequence combined with a 1.88-kb E3 deletion. It was also observed that regardless of the SV40 sequences flanking the reporter gene or the E3 deletion used, expression from the luciferase recombinants was dependent on vital DNA replication, whereas expression from the LacZ recombinants was only partially reduced when DNA replication was blocked. Analyses of RNA by dot blot hybridizations revealed that the levels of reporter gene-specific mRNA for various vectors in each series did not vary significantly. These results indicate that the kinetics and efficiency of expression of genes inserted into the E3 region, in nonconditional helper-independent vectors, may be more strongly dependent on the sequences in the foreign gene insert itself than on flanking regulatory sequences such as those used here, derived from SV40