Project description:Eco1 is the acetyltransferase that establishes sister-chromatid cohesion during DNA replication. Budding yeast with an eco1 mutation that genocopies Roberts syndrome displaysreduced ribosomal DNA (rDNA) transcription and a transcriptional signature of starvation. Weshow that deleting FOB1, a gene encoding a specific replication fork blocking protein for therDNA region, rescues rRNA production and partially rescues transcription genome-wide. This experiment examines the effect of eco1 mutation on replication genome-wide. Furtherstudies show that deletion of FOB1 corrects the genome-wide replication defects, nucleolarstructure, and rDNA segregation in an eco1 mutant. Our study highlights cohesin's central role atthe rDNA for global control of DNA replication and gene expression. DNA content in eco1-W216G mutant and wt yeast is measured in duplicate by sequencing at 0, 20, and 40 minutes following release from G1 arrest.
Project description:Eco1 is the acetyltransferase that establishes sister-chromatid cohesion during DNA replication. Budding yeast with an eco1 mutation that genocopies Roberts syndrome displaysreduced ribosomal DNA (rDNA) transcription and a transcriptional signature of starvation. Weshow that deleting FOB1, a gene encoding a specific replication fork blocking protein for therDNA region, rescues rRNA production and partially rescues transcription genome-wide. This experiment examines the effect of eco1 mutation on replication genome-wide. Furtherstudies show that deletion of FOB1 corrects the genome-wide replication defects, nucleolarstructure, and rDNA segregation in an eco1 mutant. Our study highlights cohesin's central role atthe rDNA for global control of DNA replication and gene expression.
Project description:Gene expression microarrays accompanying "Proteomic and genomic characterization of a yeast model for Ogden syndrome" by Doerfel et al 2016 in press at Yeast. Naa10 is a Na-terminal acetyltransferase that, in a complex with its auxiliary subunit Naa15, co-translationally acetylates the a-amino group of newly synthetized proteins as they emerge from the ribosome. Roughly 40-50% of the human proteome is acetylated by Naa10, rendering this an enzyme with one of the most broad substrate ranges known. Recently, we reported an X-linked disorder of infancy, Ogden syndrome, in two families harboring a c.109T>C (p.Ser37Pro) variant in NAA10. In the present study we performed in-depth characterization of a yeast model of Ogden syndrome. Stress tests and proteomic analyses suggest that the S37P mutation disrupts Naa10 function and reduces cellular fitness during heat shock, possibly due to dysregulation of chaperone expression and accumulation. Microarray and RNA-seq revealed a pseudo-diploid gene expression profile in DNaa10 cells, likely responsible for a mating defect. In conclusion, the data presented here further support the disruptive nature of the S37P/Ogden mutation and identify affected cellular processes potentially contributing to the severe phenotype seen in Ogden syndrome.
Project description:SSD1 is a polymorphic locus in budding yeast with many pleiotropic effects. Our lab had previously done transcript microarray of W303a in an ssd1-d background, and here we have carried out another transcript microarray across the cell cycle in an isogenic SSD1-V background. We find that a large fraction of budding yeast transcripts is differentially expressed in these cells. Ssd1 has recently been shown to bind mRNAs in vivo, but very few of these mRNAs show significant changes in levels in the SSD1-V versus ssd1-d comparison. About 20% of cell cycle-regulated transcripts are affected by SSD1-V and most of these transcripts show sharper amplitudes of oscillation in SSD1-V cells. Many transcripts whose gene products influence longevity are also affected, the largest class of which are involved in translation. Ribosomal protein mRNAs are globally down-regulated by SSD1-V.
Project description:RNAi, a gene-silencing pathway triggered by double-stranded RNA, is conserved in diverse eukaryotic species but has been lost in the model budding yeast, Saccharomyces cerevisiae. We report that RNAi is present in other budding-yeast species, including Saccharomyces castellii and Candida albicans. These species use noncanonical Dicer proteins to generate siRNAs, which mostly correspond to transposable elements and Y´ subtelomeric repeats. In S. castellii, RNAi mutants are viable but have excess Y´ mRNA levels. In S. cerevisiae, introducing Dicer and Argonaute of S. castellii restores RNAi, and the reconstituted pathway silences endogenous retrotransposons. These results identify a novel class of Dicer proteins, bring the tool of RNAi to the study of budding yeasts, and bring the tools of budding yeast to the study of RNAi.