Disruption and phenotypic analysis of six open reading frames from the left arm of Saccharomyces cerevisiae chromosome VII

Six open reading frames (ORFs) from Saccharomyces cerevisiae chromosome VII were deleted using the kanMX4 module and the long-flanking homology-PCR replacement strategy in at least two different backgrounds. Among these ORFs, two of them (YGL100w and YGL094c) are now known genes which encode well-characterized proteins (Seh1p, a nuclear pore protein, and Pan2p, a component of Pab1p-stimulated poly(A) ribonuclease, respectively). The other four ORFs (YGL101w, YGL099w, YGL098w and YGL096w) code for proteins of unknown function, although the protein encoded by YGL101w has a strong similarity to the hypothetical protein Ybr242p. Gene disruptions were performed in diploid cells using the KanMX4 cassette, and the geneticin (G418)-resistant transformants were checked by PCR. Tetrad analysis of heterozygous deletant strains revealed that YGL098w is an essential gene for vegetative growth in three backgrounds, whereas the other five genes are non-essential, although we have found some phenotypes in one of them. YGL099wDelta strain did not grow at all at 15 degrees C and showed a highly impaired sporulation and a significantly lower mating efficiency. The other three deletants did not reveal any significant differences with respect to their parental strains in our basic phenotypic tests.