Project description:Nitric oxide being a versatile molecule inside biological systems, from being both a cell signaling molecule to a potent stress agent, has significant effect in the transcriptional response in fission yeast. We have used fission yeast microarrays to identify cellular targets of Nitric Oxide (NO) and to further understand the cellular mechanism of NO action. We report the change in the global gene expression profile response to NO in S. pombe cells
Project description:Mitogen Activated Protein Kinase (MAPK) signaling cascades transduce information arising from events external to the cell, such as environmental stresses, to a variety of downstream effectors and transcription factors. The fission yeast stress activated MAP kinase (SAPK) pathway is conserved with the p38 and JNK pathways in humans, and comprises the MAPKKKs Win1, Wis4, the MAPKK Wis1, and the MAPK, Sty1. Sty1 and its main downstream effector Atf1 regulate a large set of core environmental stress response genes. The fission yeast genome encodes three other ATF proteins: Atf21, Atf31 and Pcr1. Among these, atf21 is specifically induced under conditions of high osmolarity. We have therefore instigated a programme to investigate the role played by non coding RNAs (ncRNAs) in response to osmotic stress challenge in wild type and atf21Δ cells. By integrating global proteomics and RNA sequencing data, we identified a systematic program in which elevated antisense RNAs arising both from ncRNAs and from 3'-overlapping convergent gene-pairs is directly associated with substantial reductions in protein levels throughout the fission yeast genome. We also found an extensive array of ncRNAs with trans associations that have the potential to influence different biological processes and stress responses in fission yeast, suggesting ncRNAs comprise additional components of the SAPK regulatory system.
Project description:Exposure of Saccharomyces cerevisiae to alkaline pH represents a stress condition that generates a compensatory reaction. Here we examine a possible role of the protein kinase-A (PKA) pathway in this response. The phenotypic analysis reveals that mutations that activate the PKA pathway (ira1 ira2, bcy1) tend to cause sensitivity to alkaline pH, whereas its deactivation develops tolerance to this stress. We observe that alkalinization causes a transient decrease in cAMP, the main regulator of the pathway. Alkaline pH causes rapid nuclear localization of the PKA-regulated Msn2 transcription factor which, together with Msn4, mediates a general stress response by binding to STRE sequences in many promoters. Consequently, a synthetic STRE-LacZ reporter shows a rapid induction in response to alkaline stress. An msn2 msn4 mutant is sensitive to alkaline pH, and transcriptomic analysis reveals that after 10 minutes of alkaline stress, the expression of many induced genes (47%) depends, at least in part, on the presence of Msn2 and Msn4. Taken together, these results demonstrate that inhibition of the PKA pathway by alkaline pH represents a substantial part of the adaptive response to this kind of stress and that this response involves Msn2/Msn4-mediated gene remodeling. However, the relevance of attenuation of PKA in high pH tolerance is not restricted to regulation of Msn2 function. Eight samples were analyzed: WT and the MCY5278 mutant strain, lacking both Msn2 and Msn4, in the presence of 20 mM KOH (pH 8) and in the presence of 20 mM KCl (non-induced conditions) for 10 and 30 min of stress. 2 biological replicates were analyzed for each condition, and dye-swapping was carried out for each comparison of samples. We compared the expression profiles of: 1) WT +KOH vs. WT +KCl after 10 min 2) msn2 msn4 mutant +KOH vs. msn2 msn4 +KCl after 10 min 3)WT +KOH vs. WT +KCl after 30 min 4) msn2 msn4 mutant +KOH vs. msn2 msn4 +KCl after 30 min Total number of chips analyzed: 16.
Project description:Crosslinking-MS analysis of sulfo-SDA crosslinked fission yeast condensin-DNA samples in the initial binding state (absence of nucleotide) and in the DNA gripping state (in the presence of ADP•BeF3)