Project description:Transcription can be quite disruptive for chromatin so cells have evolved mechanisms to preserve chromatin integrity during transcription, hence preventing the emergence of cryptic transcript from spurious promoter sequences. How these transcripts are regulated and processed by cells remains poorly characterized. Notably, very little is known about the termination of cryptic transcription. Here we used RNA-Seq to identify and characterize cryptic transcripts in Spt6 mutant cells (spt6-1004) in Saccharomyces cerevisiae. We found polyadenylated cryptic transcripts running both sense and anti-sense relative to genes in this mutant. Cryptic promoters were enriched for TATA boxes, suggesting that the underlying DNA sequence defines the location of cryptic promoters. While intragenic sense cryptic transcripts terminate at the terminator of the genes that host them, we found that anti-sense cryptic transcripts preferentially terminate at the 3’-end of upstream genes. These findings led us to demonstrate that most terminators in yeast are bidirectional, leading to termination and polyadenylation of transcripts coming from either direction. We propose that S. cerevisiae has evolved this mechanism in order to prevent spurious transcription from invading neighbouring genes, a feature particularly critical for organisms with small compact genomes.
Project description:We sequenced both the stable (WT) and unstable (rrp6delta) transcriptomes of three S.cerevisiae strains: S288c, Σ1278b, JAY291 and the S.paradoxus strain N17 for de novo annotation of cryptic unstable transcripts (CUTs). Doing so we have greatly expanded on previous CUTs which were limited to the S.cerevisiae strain S288c and have provided the first assessment of CUT expression conservation in yeast
Project description:Long non-coding RNAs (lncRNAs) have been shown to regulate gene expression, chromatin domains and chromosome stability in eukaryotic cells. Recent observations have reported the existence of telomere associated long ncRNAs (TERRA, telomeric repeat containing RNA) in mammalian and yeast cells but their function(s) remain(s) poorly characterized. Here, we report the existence in S. cerevisiae of several sense and antisense Cryptic Unstable Transcripts (CUTs) and Xrn1-sensitive Unstable Transcripts (XUT) initiating within the subtelomeric repeated region Y’. We show that the Y’ ncRNAs, subTERRA, are distinct from TERRA and are mainly destabilized by the general cytoplasmic and nuclear 5’- and 3’- RNA decays in a sense-dependent manner. subTERRA transcription is mainly sustained by RNAPII and subTERRA accumulate preferentially during the G1/S transition and in C-terminal rap1 mutants independently of Rap1p function in silencing. The accumulation of subTERRA in RNA decay mutants coincides with telomere misregulation: shortening of telomere length, loss of telomeric clustering in mitotic cells, indicating that subTERRA might compete with factors involved in telomere elongation, tethering and/or clustering. We propose that subtelomeric RNAs expression links telomere maintenance with RNA degradation pathways. Exmination of two yeast mutants for RNA decay.
Project description:In this study we show that disruption of NC2 function by shutting off either of its two protein subunits in yeast provokes an immediate increase in cryptic transcription around and inside any kind of RNA pol II genes.
Project description:In cells lacking the histone methyltransferase Set2, initiation of RNA polymerase II transcription occurs inappropriately within the protein-coding regions of genes, rather than being restricted to the proximal promoter. Here, we mapped the transcripts produced in an S. cerevisiae strain lacking Set2, and applied rigorous statistical methods to identify sites of cryptic transcription at high resolution.
Project description:Long non-coding RNAs (lncRNAs) have been shown to regulate gene expression, chromatin domains and chromosome stability in eukaryotic cells. Recent observations have reported the existence of telomere associated long ncRNAs (TERRA, telomeric repeat containing RNA) in mammalian and yeast cells but their function(s) remain(s) poorly characterized. Here, we report the existence in S. cerevisiae of several sense and antisense Cryptic Unstable Transcripts (CUTs) and Xrn1-sensitive Unstable Transcripts (XUT) initiating within the subtelomeric repeated region Y’. We show that the Y’ ncRNAs, subTERRA, are distinct from TERRA and are mainly destabilized by the general cytoplasmic and nuclear 5’- and 3’- RNA decays in a sense-dependent manner. subTERRA transcription is mainly sustained by RNAPII and subTERRA accumulate preferentially during the G1/S transition and in C-terminal rap1 mutants independently of Rap1p function in silencing. The accumulation of subTERRA in RNA decay mutants coincides with telomere misregulation: shortening of telomere length, loss of telomeric clustering in mitotic cells, indicating that subTERRA might compete with factors involved in telomere elongation, tethering and/or clustering. We propose that subtelomeric RNAs expression links telomere maintenance with RNA degradation pathways.
Project description:Long-term effects of imatinib, a chemotherapy agent, on S. cerevisiae cells were investigated. Yeast cells were grown in the absence and presence of 400 mg/l imatinib in fully controlled bioreactors, in triplicates. Control cultures were described before, E-MTAB-6634.