Search

The Candida glabrata (CgKRE9) and KNH1 (CgKNH1) genes were isolated as multicopy suppressors of the tetracycline-responsive growth of a Saccharomyces cerevisiae mutant with the damaged KNH1 locus and the KRE9 gene regulated by a tetracycline-sensitive promoter. Disruption of CgKRE9 resulted in several phenotypes similar to those of the S. cerevisiae kre9-delta null mutant, massive growth defect on glucose medium, resistance to the K1 killer toxin, a 50% decrease in beta-1,6-glucan and the presence of groups of cells with abnormal morphology on glucose medium.

We have isolated CaKRE9, a gene from Candida albicans, that is a functional homologue of the Saccharomyces cerevisiae KRE9 gene involved in [Beta]-1,6-glucan synthesis. Disruption of the CaKRE9 gene in C. albicans shows that CaKre9p is required for the synthesis or assembly of this fungal polymer. Homozygous null disruptants of CaKRE9 grow poorly on galactose and fail to form hyphae in serum, and, in growth medium containing glucose, the gene is essential. Thus, the CaKRE9 gene product is a potentially useful candidate as a target for fungal-specific drugs.

The sequenced yeast genome offers a unique resource for the analysis of eukaryotic cell function and enables genome-wide screens for genes involved in cellular processes. We have identified genes involved in cell surface assembly by screening transposon-mutagenized cells for altered sensitivity to calcofluor white, followed by supplementary screens to further characterize mutant phenotypes. The mutated genes were directly retrieved from genomic DNA and then matched uniquely to a gene in the yeast genome database. Eighty-two genes with apparent perturbation of the cell surface were identified, with mutations in 65 of them displaying at least one further cell surface phenotype in addition to their modified sensitivity to calcofluor. Fifty of these genes were previously known, 17 encoded proteins whose function could be anticipated through sequence homology or previously recognized phenotypes and 15 genes had no previously known phenotype.

Mutations in the Caenorhabditis elegans gene clk-1 affect biological timing and extend longevity. The gene clk-1 was identified, and the cloned gene complemented the clk-1 phenotypes and restored normal longevity. The CLK-1 protein was found to be conserved among eukaryotes, including humans, and structurally similar to the yeast metabolic regulator Cat5p (also called Coq7p). These proteins contain a tandem duplication of a core 82-residue domain. clk-1 complemented the phenotype of cat5/coq7 null mutants, demonstrating that clk- 1 and CAT5/COQ7 share biochemical function and that clk-1 acts at the level of cellular physiology., The activity of clk-1 in the nematode Caenorhabditis elegans controls the rate of the worms' development, the pace of their behaviors, and when they die (1). In clk-1 mutants, the [...]

The correct localization of the Saccharomyces cerevisiae Kre2p/Mnt1p alpha-1,2-mannosyltransferase membrane protein in the Golgi body requires the short NH2-terminal cytoplasmic tail domain of Kre2p. The membrane spanning and the stem regions of the Kre2p protein are not necessary for this process. The Kre2p protein is localized in a Golgi compartment that extends over the compartment containing the medial-Golgi mannosyltransferase Mnn1p. The Kre2p/Mnt1p protein has a type II orientation that is N-glycosylated in an MNNI-dependent fashion.

Author(s): Guri Giaever [1]; Angela M. Chu [2]; Li Ni [3]; Carla Connelly [4]; Linda Riles [5]; Steeve Véronneau [6]; Sally Dow [7]; Ankuta Lucau-Danila [8]; Keith Anderson [1]; Bruno [...]

The functions of many open reading frames (ORFs) identified in genomesequencing projects are unknown. New, whole-genome approaches are required to systematically determine their function. A total of 6925 Saccharomyces cerevisiae strains were constructed, by a high-throughput strategy, each with a precise deletion of one of 2026 ORFs (more than one-third of the ORFs in the genome). Of the deleted ORFs, 17 percent were essential for viability in rich medium. The phenotypes of more than 500 deletion strains were assayed in parallel Of the deletion strains, 40 percent showed quantitative growth defects in either rich or minimal medium., The budding yeast S. cerevisiae serves as an important experimental organism for revealing gene function. In addition to carrying out all the basic functions of eukaryotic cells, up to 30% [...]