Project description:Purpose: Saccharomyceatacea yeast are intron-poor species and they contain on average 300 introns in their genomes. We designed RNAseq experiment to investigate if splicing patterns in related yeast species are similar. Methods: Total RNA was extracted from wild type cells and processed by the RiboMinus Transcriptome Isolation Kit for Yeast and Bacteria (Invitrogen) to deplete the rRNA. cDNA libraries were prepared according to manufacturer's protocol and sequenced by SOLiD. Sequence reads were filtered and processed by TopHat. Results: We found 216, 163, 200 and 155 predicted introns with canonical splice signals in S. cerevisiae, S. kudriavzevii, S. bayanus and N. castellii respectively. Three introns in S. cerevisiae, four in S. bayanus and ten in S. castellii are novel compared to Saccharomyces Genome Database (SGD) annotations. The expression of introns and splicing shows very high correlation between species. Conclusion: Transcripts with introns in yeast species tested show similar levels of expression and splicing. We found few novel introns, which are conserved in yeast genomes.
Project description:Ribosomal proteins are essential to life. While the functions of ribosomal protein-encoding genes (RPGs) are highly conserved, the evolution of their regulatory mechanisms is remarkably dynamic. In Saccharomyces cerevisiae, RPGs are unusual in that they are commonly present as two highly similar gene copies and that they are over-represented among intron-containing genes. To investigate the role of introns in the regulation of RPG expression, we constructed 16 S. cerevisiae strains with precise deletions of RPG introns. We found that several yeast introns function to repress rather than to increase steady-state mRNA levels. Among these, the RPS9A and RPS9B introns were required for cross-regulation of the two paralogous gene copies, which is consistent with the duplication of an autoregulatory circuit. Splicing specific microarrays were used to assess the genome-wide defects in gene expression and pre-mRNA splicing that result from a deletion of a single ribosomal protein gene intron.
Project description:Ribosomal proteins are essential to life. While the functions of ribosomal protein-encoding genes (RPGs) are highly conserved, the evolution of their regulatory mechanisms is remarkably dynamic. In Saccharomyces cerevisiae, RPGs are unusual in that they are commonly present as two highly similar gene copies and that they are over-represented among intron-containing genes. To investigate the role of introns in the regulation of RPG expression, we constructed 16 S. cerevisiae strains with precise deletions of RPG introns. We found that several yeast introns function to repress rather than to increase steady-state mRNA levels. Among these, the RPS9A and RPS9B introns were required for cross-regulation of the two paralogous gene copies, which is consistent with the duplication of an autoregulatory circuit.
Project description:We present an analysis of intron retention under stress from two different drugs and their combinations in yeast Saccharomyces cerevisiae. We previously established isogrowth profiling, a method to abstract the non-specific effects of growth rate inhibition from the specific effect of perturbation by a small molecule: two drugs are used at varied ratios, but at fixed overall growth inhibition. Here, cycloheximide and LiCl were used at seven different ratios along the 50% growth inhibition isobole and the total ribodepleted RNA was sequenced. This allowed us to gauge the changes in intron retention due to the used drugs, while ensuring that the effects are not caused by growth inhibition. We found a prominent increase in intron retention under LiCl treatment that preferentially affects introns contained in the transcripts of ribosomal proteins.
Project description:Exon-intron circRNA (EIciRNA) is a subclass of backsplicing-generated circRNAs featured with intron retention, among which some play roles in transcriptional regulation. We aim to characterize EIciRNAs by developing pipeline and investigate the factors involved in regulating EIciRNA biogenesis using CRISPR-Cas9 screen, as well as the physiology functions of EIciRNAs during neuronal differentiation.
Project description:Exon-intron circRNA (EIciRNA) is a subclass of backsplicing-generated circRNAs featured with intron retention, among which some play roles in transcriptional regulation. We aim to characterize EIciRNAs by developing pipeline and investigate the factors involved in regulating EIciRNA biogenesis using CRISPR-Cas9 screen, as well as the physiology functions of EIciRNAs during neuronal differentiation.