Project description:Most eukaryotic genes express mRNAs with alternative polyadenylation sites at their 3’ ends. Here we show that polyadenylated 3’ termini in three yeast species (S. cerevisiae, K. lactis, D. hansenii) are remarkably heterogeneous. Instead of a few discrete 3’ ends, the average yeast gene has an “end zone”, a >200 bp window with >60 distinct poly(A) sites, the most utilized of which represents only 20% of the mRNA molecules. The pattern of polyadenylation within this zone varies across species, with D. hansenii possessing a higher focus on a single dominant point closer to the ORF terminus. Some polyadenylation occurs within mRNA coding regions with a strong bias towards the promoter. The polyadenylation pattern is determined by a highly degenerate sequence over a broad region and by a local sequence that relies on A residues after the cleavage point. Many dominant poly(A) sites are predicted to adopt a common secondary structure that may be recognized by the cleavage/polyadenylation machinery. We suggest that the end zone reflects a region permissive for polyadenylation, within which cleavage occurs preferentially at the A-rich sequence. In S. cerevisiae strains, D. hansenii genes adopt the S. cerevisiae polyadenylation profile, indicating that the polyadenylation pattern is mediated primarily by species-specific factors. Four sequencing lanes containing direct RNA sequence from S. cerevisiae (strains JGY2000 and two replicates of AB1380), K. lactis strain CLIB209, D. hansenii strain NCYC2572, and S. cerevisiae strains JYAC06 and JYAC07, each harboring D. hansenii sequences on a YAC. AB1380 is the non-YAC-containing S. cerevisiae parental strain for JYAC06 and JYAC07.
Project description:Most eukaryotic genes express mRNAs with alternative polyadenylation sites at their 3’ ends. Here we show that polyadenylated 3’ termini in three yeast species (S. cerevisiae, K. lactis, D. hansenii) are remarkably heterogeneous. Instead of a few discrete 3’ ends, the average yeast gene has an “end zone”, a >200 bp window with >60 distinct poly(A) sites, the most utilized of which represents only 20% of the mRNA molecules. The pattern of polyadenylation within this zone varies across species, with D. hansenii possessing a higher focus on a single dominant point closer to the ORF terminus. Some polyadenylation occurs within mRNA coding regions with a strong bias towards the promoter. The polyadenylation pattern is determined by a highly degenerate sequence over a broad region and by a local sequence that relies on A residues after the cleavage point. Many dominant poly(A) sites are predicted to adopt a common secondary structure that may be recognized by the cleavage/polyadenylation machinery. We suggest that the end zone reflects a region permissive for polyadenylation, within which cleavage occurs preferentially at the A-rich sequence. In S. cerevisiae strains, D. hansenii genes adopt the S. cerevisiae polyadenylation profile, indicating that the polyadenylation pattern is mediated primarily by species-specific factors.
Project description:Most eukaryotic genes express mRNAs with alternative polyadenylation sites at their 3' ends. Here we show that polyadenylated 3' termini in three yeast species (Saccharomyces cerevisiae, Kluyveromyces lactis, and Debaryomyces hansenii) are remarkably heterogeneous. Instead of a few discrete 3' ends, the average yeast gene has an "end zone," a >200 bp window with >60 distinct poly(A) sites, the most used of which represents only 20% of the mRNA molecules. The pattern of polyadenylation within this zone varies across species, with D. hansenii possessing a higher focus on a single dominant point closer to the ORF terminus. Some polyadenylation occurs within mRNA coding regions with a strong bias toward the promoter. The polyadenylation pattern is determined by a highly degenerate sequence over a broad region and by a local sequence that relies on A residues after the cleavage point. Many dominant poly(A) sites are predicted to adopt a common secondary structure that may be recognized by the cleavage/polyadenylation machinery. We suggest that the end zone reflects a region permissive for polyadenylation, within which cleavage occurs preferentially at the A-rich sequence. In S. cerevisiae strains, D. hansenii genes adopt the S. cerevisiae polyadenylation profile, indicating that the polyadenylation pattern is mediated primarily by species-specific factors.
Project description:Transcriptome response of the yeasts C. glabrata and S. cerevisiae treated by an antifungal agent, benomyl Keywords: time course; stress response
Project description:Several general principles of global 3D genome organization have recently been established, including non-random positioning of chromosomes and genes in the cell nucleus, distinct chromatin compartments, and topologically associating domains (TADs). However, the extent and nature of cell-to-cell and cell-intrinsic variability in genome architecture are still poorly characterized. Here, we systematically probe heterogeneity in genome organization. High-throughput optical mapping of several hundred intra-chromosomal interactions in individual human fibroblasts demonstrates low association frequencies, which are determined by genomic distance, higher-order chromatin architecture, and chromatin environment. The structure of TADs is variable between individual cells, and inter-TAD associations are common. Furthermore, single-cell analysis reveals independent behavior of individual alleles in single nuclei. Our observations reveal extensive variability and heterogeneity in genome organization at the level of individual alleles and demonstrate the coexistence of a broad spectrum of genome configurations in a cell population.
Project description:Transcriptome response of the yeasts C. glabrata and S. cerevisiae treated by an antifungal agent, benomyl Keywords: time course; stress response We performed microarray analyses of the transcriptome response of the yeasts Candida glabrata and Saccharomyces cerevisiae, treated by an antifungal agent, benomyl. The C. glabrata cells were submitted to 20 μg/mL of benomyl for 2, 4, 10, 20, 40 and 80 minutes. The labelled cDNA from treated cells were competitively hybridized on microarrays versus cDNA from mock treated cells.