Identification and characterization of <i>Saccharomyces cerevisiae EXO1</i> , a gene encoding an exonuclease that interacts with MSH2Daniel X. Tishkoff, Adrienne L. Boerger, Pascale Bertrand et al.|Proceedings of the National Academy of Sciences|1997 A two-hybrid screen was used to identify Saccharomyces cerevisiae genes encoding proteins that interact with MSH2. One gene was found to encode a homologue of Schizosaccharomyces pombe EXO1, a double-stranded DNA-specific 5'-3' exonuclease. S. cerevisiae EXO1 interacted with both S. cerevisiae and human MSH2 in two-hybrid and coimmunoprecipitation experiments. exo1 mutants showed a mutator phenotype, and epistasis analysis was consistent with EXO1 functioning in the MSH2-dependent mismatch repair pathway. exo1 mutations were lethal in combination with rad27 mutations, and overexpression of EXO1 suppressed both the temperature sensitive and mutator phenotypes of rad27 mutants.
Retroviral Entry Mediated by Receptor Priming and Low pH Triggering of an Envelope GlycoproteinRetroviral vectors preloaded with a viral receptor-ligand bridge protein are targeted to specific cell typesAdrienne L. Boerger, Sophie Snitkovsky, John A. T. Young|Proceedings of the National Academy of Sciences|1999 Successful targeting methods represent a major hurdle to the use of retroviral vectors in cell-specific gene-delivery applications. We recently described an approach for retroviral targeting with a retroviral receptor-ligand bridge protein that was bound to the cognate cell-surface ligand receptors before viral challenge. We now report a significant improvement made to this viral targeting method by using a related bridge protein, designated TVB-EGF, comprised of the extracellular domain of the TVB receptor for subgroup B avian leukosis virus fused to epidermal growth factor (EGF). The most important activity of TVB-EGF was that it allowed specific viral entry when preloaded onto virions. Furthermore, virions preloaded with TVB-EGF were thermostable and could be produced directly from virus- packaging cells. These data suggest an approach for targeting retroviral vectors to specific cell types by using virions preloaded with a retroviral receptor-ligand bridge protein and indicate that these types of bridge proteins may be useful reagents for studying the normal mechanism of retroviral entry.
P III B.10 Identification and characterization of exo/endonucleases involved in mutation avoidance in S. cerevisiaeDaniel X. Tishkoff, Pascale Bertrand, Adrienne L. Boerger et al.|Mutation research. Fundamental and molecular mechanisms of mutagenesis|1997 Identification and characterization of Saccharomyces cerevisiae EXO1, a gene encoding an exonuclease that interacts with MSH2A two-hybrid screen was used to identify Saccharomyces cerevisiae genes encoding proteins that interact with MSH2. One gene was found to encode a homologue of Schizosaccharomyces pombe EXO1, a double-stranded DNA-specific 5′–3′ exonuclease. S. cerevisiae EXO1 interacted with both S. cerevisiae and human MSH2 in two-hybrid and coimmunoprecipitation experiments. exo1 mutants showed a mutator phenotype, and epistasis analysis was consistent with EXO1 functioning in the MSH2-dependent mismatch repair pathway. exo1 mutations were lethal in combination with rad27 mutations, and overexpression of EXO1 suppressed both the temperature sensitive and mutator phenotypes of rad27 mutants.