title: The deletion of six ORFs of unknown function from Saccharomyces cerevisiae chromosome VII reveals two essential genes: YGR195w and YGR198w.
abstract: We have deleted six different ORFs of unknown function located on the right arm of Saccharomyces cerevisiae chromosome VII; namely, YGR187c/HGH1, YGR189c, YGR194c, YGR195w, YGR196c and YGR198w. No basic phenotypes could be attributed to the strains deleted in any of genes YGR187c/HGH1, YGR189c, YGR194c and YGR196c. These deletants did not show mating, sporulation or growth defects under any of the conditions tested. However, spores bearing deletions in either the YGR195w or YGR198w genes were unable to develop into macroscopical colonies. The YGR195w gene product shows significant homology with bacterial ribonuclease PH, an enzyme hitherto undescribed in yeasts, and its deletion causes a loss of viability after one to three rounds of cell division. Overexpression of this gene, using a tetracycline-regulatable promoter system, did not cause any effect on the cells. Contrary to what has been reported for prokaryotic homologs, this enzyme could play an essential role in yeast cell biology. The product encoded by the other essential ORF, YGR198w, shows no significant homology with any protein of known function in the databases. Spores bearing the deletion usually germinate and give rise to microcolonies of 50-100 non-viable cells.
authors.affiliation: Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense, Madrid, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Rodriguez-Peña
authors.forename: V J
authors.initials: VJ
authors.lastname: Cid
authors.forename: M
authors.initials: M
authors.lastname: Sanchez
authors.forename: M
authors.initials: M
authors.lastname: Molina
authors.forename: J
authors.initials: J
authors.lastname: Arroyo
authors.forename: C
authors.initials: C
authors.lastname: Nombela
mesh_terms: D015825:Chromosomes, Fungal / Q000235:genetics; D005095:Exoribonucleases / Q000378:metabolism; D063326:Exosome Multienzyme Ribonuclease Complex; D017353:Gene Deletion; D020043:Genes, Essential; D005800:Genes, Fungal / Q000235:genetics*; D016366:Open Reading Frames / Q000235:genetics*; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D013172:Spores, Fungal / Q000502:physiology
chemical_list: C111978:SKI6 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C056502:ribonuclease PH; D005095:Exoribonucleases; D063326:Exosome Multienzyme Ribonuclease Complex