Mutations in the Saccharomyces cerevisiae gene SAC1 cause multiple drug sensitivity.

Wild-type yeast Saccharomyces cerevisiae are surprisingly resistant to a wide range of drugs and agents. We had previously isolated novobiocin-sensitive mutants to aid the study of the intracellular target for this drug. Characterization of one of these mutants, mds1, revealed that it was sensitive not only to novobiocin but also to a wide range of drugs.

Complete sequence of the IncPbeta plasmid R751: implications for evolution and organisation of the IncP backbone.

The broad host range IncP plasmids are of particular interest because of their ability to promote gene spread between diverse bacterial species. To facilitate study of these plasmids we have compiled the complete sequence of the IncPbeta plasmid R751. Comparison with the sequence of the IncPalpha plasmids confirms the conservation of the IncP backbone of replication, conjugative transfer and stable inheritance functions between the two branches of this family.

Distribution of restriction enzyme recognition sequences on broad host range plasmid RP4: molecular and evolutionary implications.

IncP alpha plasmids, exemplified by RP4, are remarkable for their broad host range. They contain strikingly few cleavage sites for many commonly used type II restriction enzymes but an overabundance of sites for certain enzymes that target G + C-rich sequences. To identify factors responsible for these distributions, the recently compiled nucleotide sequence of RP4 was analysed to determine the frequency of tetra- and hexanucleotide motifs in the 49 kb plasmid backbone.

Novobiocin activates the mating response in yeast through the alpha-pheromone receptor, Ste2p.

In a previous publication we reported the isolation of several yeast mutants sensitive to the coumarin drug novobiocin. Here we characterise the wild-type gene (NBS5), obtained by rescuing a novobiocin-sensitive nbs5 strain to natural novobiocin resistance. We show that nbs5 is allelic to the previously characterised gene sst2, conferring super-sensitivity to the mating pheromones.

Characterization of PKC2, a gene encoding a second protein kinase C isotype of Saccharomyces cerevisiae.

Background: Protein kinase C (PKC) has attracted considerable attention over the past decade, primarily because of its presumed role in cellular growth control and tumourigenesis. Mammalian cells express at least 10 different isozymes of PKC; it is this complexity that has made elucidating the precise functions of PKC: so difficult. The identification of PKC homologues in organisms such as Drosophila, Xenopus, Dictyostelium, Aplysia and Caenorhabditis indicates that the enzyme is evolutionarily conserved, and this has stimulated our search for counterparts in the yeast Saccharomyces cerevisiae, in which powerful genetic analyses can be used.