Project description:CHX is an inhibitor of translation elongation often used in ribosome profiling experiments. There is evidence that CHX treatment of cells may cause artefacts in the distribution of ribosomes on mRNAs. We investigate this possibility in S. pombe by performing ribosome profiling in the presence and absence of this drug.
Project description:To examine whether naturally occurring duplications are altering gene expression we chose eight pairs of closely related strains (less than 150 SNPS between each pair) that contained at least one unshared duplication and performed pair-wise two-colour microarray analysis.
Project description:To estimate mRNA steady-state levels we used RNA extracted from logarithmically growing fisson yeast cells on Affymetrix Yeast 2.0 Genechip arrays. The signal intensities from two independent biological repeats were averaged, resulting in measurements for 4818 out of 4962 nuclear protein-coding genes.
Project description:General discard pathways eliminate unprocessed and irregular pre-mRNAs to control the quality of gene expression. In contrast to such general pre-mRNA decay, we describe here a nuclear pre-mRNA degradation pathway that controls the expression of select intron-containing genes. We show that the fission yeast nuclear poly(A)-binding protein, Pab2, and the nuclear exosome subunit, Rrp6, are the main factors involved in this polyadenylation-dependent pre-mRNA degradation pathway. Transcriptome analysis and intron swapping experiments revealed that inefficient splicing is important to dictate susceptibility to Pab2-dependent pre-mRNA decay. We also show that negative splicing regulation can promote the poor splicing efficiency required for this pre-mRNA decay pathway, and in doing so identify a mechanism of cross-regulation between paralogous ribosomal proteins through nuclear pre-mRNA decay. Our findings unveil a layer of regulation in the nucleus in which the turnover of specific pre-mRNAs, besides the turnover of mature mRNAs, is used to control gene expression.
Project description:Data on absolute molecule numbers are rare but will empower the modeling, understanding and comparison of cellular functions and biological systems. We quantified transcriptomes and proteomes in fission yeast during both proliferation and quiescence. This rich resource provides the first comprehensive reference for all RNA and most protein concentrations in a eukaryote under key physiological conditions. This integrated dataset will support quantitative biology and afford unique biological insights into cell regulation. While mRNAs are typically expressed in a narrow range above 1 copy/cell, most long non-coding RNAs, except for a specific subset, are strongly repressed below 1 copy/cell. Cell cycle-regulated transcription tunes mRNA numbers to phase-specific requirements but can also lead to switch-like expression. Proteins greatly exceed mRNAs in abundance and dynamic range, and their numbers scales with functional demands. Upon transition to quiescence, the proteome composition changes substantially but, in stark contrast to mRNAs, proteins do not uniformly decrease but scale with cell volume.