Kevin S. Johnson

Bio: Kevin S. Johnson is an academic researcher from University of Melbourne. The author has contributed to research in topics: Antigen & Oncosphere. The author has an hindex of 4, co-authored 5 publications receiving 6250 citations.

Vaccination against ovine cysticercosis using a defined recombinant antigen.

Abstract: Cysticercosis caused by larval tapeworms is a major public health problem and a cause of substantial economic losses in the farm-animal industries. Taenia ovis in sheep is a particularly important example. Immunity to reinfection with the larvae has a central role in regulating natural transmission of the parasites, and vaccination with antigens from the early larval oncosphere stage can induce complete protection against infection. As it is impractical to obtain enough oncospheres for a commercial vaccine against these tapeworms, an alternative approach is to use recombinant DNA methods to generate a cheap and plentiful supply of antigens. We report here the expression in Escherichia coli of complementary DNA encoding T. ovis antigens as fusion proteins with the Schistosoma japonicum glutathione S-transferase. Vaccination of sheep with these fusion proteins gave significant, although not complete, immunity against challenge infection with T. ovis eggs. Commercial development of a vaccine is being pursued.

Antigenic polypeptides of Taenia ovis

Abstract: This invention relates to polypeptide antigens of T.ovis suitable for use in vaccines to protect ruminants against infection by cestode parasites. The antigens are preferably obtained by expression of DNA coding therefor in a recombinant host cell. Aspects of the invention include DNA encoding the antigens, vectors containing the DNA and hosts which express the antigens. The invention also provides antibody and DNA probes for use in identifying protective antigens of cestode parasites other than T.ovis.

Vaccines comprising antigenic polypeptides of Taenia ovis

Abstract: This invention relates to polypeptide antigens of T.ovis suitable for use in vaccines to protect ruminants against infection by cestode parasites, The antigens are preferably obtained by expression of DNA coding therefor in a recombinant host cell. Aspects of the invention include DNA encoding the antigens, vectors containing the DNA and hosts which express the antigens. The invention also provides antibody and DNA probes for use in identifying protective antigens of cestode parasites other than T.ovis.

Oligomerization and phosphorylation of the Ire1p kinase during intracellular signaling from the endoplasmic reticulum to the nucleus.

Abstract: The transmembrane kinase Ire1p is required for activation of the unfolded protein response (UPR), the increase in transcription of genes encoding endoplasmic reticulum (ER) resident proteins that occurs in response to the accumulation of unfolded proteins in the ER. Ire1p spans the ER membrane (or the nuclear membrane with which the ER is continuous), with its kinase domain localized in the cytoplasm or in the nucleus. Consistent with this arrangement, it has been proposed that Ire1p senses the accumulation of unfolded proteins in the ER and transmits the signal across the membrane toward the transcription machinery, possibly by phosphorylating downstream components of the UPR pathway. Molecular genetic and biochemical studies described here suggest that, as in the case of growth factor receptors of higher eukaryotic cells, Ire1p oligomerizes in response to the accumulation of unfolded proteins in the ER and is phosphorylated in trans by other Ire1p molecules as a result of oligomerization. In addition to its kinase domain, a C-terminal tail domain of Ire1p is required for induction of the UPR. The role of the tail is probably to bind other proteins that transmit the unfolded protein signal to the nucleus.

LC3, a mammalian homologue of yeast Apg8p, is localized in autophagosome membranes after processing

Abstract: Little is known about the protein constituents of autophagosome membranes in mammalian cells. Here we demonstrate that the rat microtubule-associated protein 1 light chain 3 (LC3), a homologue of Apg8p essential for autophagy in yeast, is associated to the autophagosome membranes after processing. Two forms of LC3, called LC3-I and -II, were produced post-translationally in various cells. LC3-I is cytosolic, whereas LC3-II is membrane bound. The autophagic vacuole fraction prepared from starved rat liver was enriched with LC3-II. Immunoelectron microscopy on LC3 revealed specific labelling of autophagosome membranes in addition to the cytoplasmic labelling. LC3-II was present both inside and outside of autophagosomes. Mutational analyses suggest that LC3-I is formed by the removal of the C-terminal 22 amino acids from newly synthesized LC3, followed by the conversion of a fraction of LC3-I into LC3-II. The amount of LC3-II is correlated with the extent of autophagosome formation. LC3-II is the first mammalian protein identified that specifically associates with autophagosome membranes.

Additional modules for versatile and economical PCR-based gene deletion and modification in Saccharomyces cerevisiae

Abstract: An important recent advance in the functional analysis of Saccharomyces cerevisiae genes is the development of the one-step PCR-mediated technique for deletion and modification of chromosomal genes This method allows very rapid gene manipulations without requiring plasmid clones of the gene of interest We describe here a new set of plasmids that serve as templates for the PCR synthesis of fragments that allow a variety of gene modifications Using as selectable marker the S cerevisiae TRP1 gene or modules containing the heterologous Schizosaccharomyces pombe his5 + or Escherichia coli kan r gene, these plasmids allow gene deletion, gene overexpression (using the regulatable GAL1 promoter), C- or N-terminal protein tagging [with GFP(S65T), GST, or the 3HA or 13Myc epitope], and partial N- or C-terminal deletions (with or without concomitant protein tagging) Because of the modular nature of the plasmids, they allow eYcient and economical use of a small number of PCR primers for a wide variety of gene manipulations Thus, these plasmids should further facilitate the rapid analysis of gene function in S cerevisiae ? 1998 John Wiley & Sons, Ltd