Differential gene expression signatures for cell wall integrity found in chitin synthase II (chs2Δ) and myosin II (myo1Δ) deficient cytokinesis mutants of Saccharomyces cerevisiae

<p>Abstract</p> <p>Background</p> <p>Myosin II-dependent contraction of the cytokinetic ring and primary septum formation by chitin synthase II are interdependent processes during cytokinesis in <it>Saccharomyces cerevisiae</it>. Hence, null mutants of myosin II <it>(myo1</it>Δ<it>) </it>and chitin synthase II <it>(chs2</it>Δ<it>) </it>share multiple morphological and molecular phenotypes. To understand the nature of their interdependent functions, we will seek to identify genes undergoing transcriptional regulation in <it>chs2</it>Δ strains and to establish a transcription signature profile for comparison with <it>myo1</it>Δ strains.</p> <p>Results</p> <p>A total of 467 genes were commonly regulated between <it>myo1Δ </it>and <it>chs2Δ </it>mutant strains (p ≤ 0.01). Common regulated biological process categories identified by Gene Set Enrichment Analysis (GSEA) in both gene expression profiles were: protein biosynthesis, RNA processing, and stress response. Expression of 17/20 genes in the main transcriptional fingerprint for cell wall stress was confirmed in the <it>chs2Δ </it>strain versus 5/20 for the <it>myo1Δ </it>strain. One of these genes, <it>SLT2/MPK1</it>, was up-regulated in both strains and both strains accumulated the hyperphosphorylated form of Slt2p thereby confirming that the <it>PKC1 </it>cell wall integrity pathway (CWIP) was activated by both mutations. The <it>SLT2/MPK1 </it>gene, essential for <it>myo1Δ </it>strains, was not required in the <it>chs2Δ </it>strain.</p> <p>Conclusion</p> <p>Comparison of the <it>chs2Δ </it>and <it>myo1</it>Δ gene expression profiles revealed similarities in the biological process categories that respond to the <it>chs2Δ </it>and <it>myo1</it>Δ gene mutations. This supports the view that these mutations affect a common function in cytokinesis. Despite their similarities, these mutants exhibited significant differences in expression of the main transcriptional fingerprint for cell wall stress and their requirement of the CWIP for survival.</p

Global mRNA expression analysis in myosin II deficient strains of Saccharomyces cerevisiae reveals an impairment of cell integrity functions

<p>Abstract</p> <p>Background</p> <p>The <it>Saccharomyces cerevisiae MYO1 </it>gene encodes the myosin II heavy chain (Myo1p), a protein required for normal cytokinesis in budding yeast. Myo1p deficiency in yeast (<it>myo1Δ</it>) causes a cell separation defect characterized by the formation of attached cells, yet it also causes abnormal budding patterns, formation of enlarged and elongated cells, increased osmotic sensitivity, delocalized chitin deposition, increased chitin synthesis, and hypersensitivity to the chitin synthase III inhibitor Nikkomycin Z. To determine how differential expression of genes is related to these diverse cell wall phenotypes, we analyzed the global mRNA expression profile of <it>myo1Δ </it>strains.</p> <p>Results</p> <p>Global mRNA expression profiles of <it>myo1Δ </it>strains and their corresponding wild type controls were obtained by hybridization to yeast oligonucleotide microarrays. Results for selected genes were confirmed by real time RT-PCR. A total of 547 differentially expressed genes (p ≤ 0.01) were identified with 263 up regulated and 284 down regulated genes in the <it>myo1Δ </it>strains. Gene set enrichment analysis revealed the significant over-representation of genes in the protein biosynthesis and stress response categories. The <it>SLT2/MPK1 </it>gene was up regulated in the microarray, and a <it>myo1Δslt2Δ </it>double mutant was non-viable. Overexpression of ribosomal protein genes <it>RPL30 </it>and <it>RPS31 </it>suppressed the hypersensitivity to Nikkomycin Z and increased the levels of phosphorylated Slt2p in <it>myo1Δ </it>strains. Increased levels of phosphorylated Slt2p were also observed in wild type strains under these conditions.</p> <p>Conclusion</p> <p>Following this analysis of global mRNA expression in yeast <it>myo1Δ </it>strains, we conclude that 547 genes were differentially regulated in <it>myo1Δ </it>strains and that the stress response and protein biosynthesis gene categories were coordinately regulated in this mutant. The <it>SLT2/MPK1 </it>gene was confirmed to be essential for <it>myo1Δ </it>strain viability, supporting that the up regulated stress response genes are regulated by the <it>PKC1 </it>cell integrity pathway. Suppression of Nikkomycin Z hypersensitivity together with Slt2p phosphorylation was caused by the overexpression of ribosomal protein genes <it>RPL30 </it>and <it>RPS31</it>. These ribosomal protein mRNAs were down regulated in the <it>myo1Δ </it>arrays, suggesting that down regulation of ribosomal biogenesis may affect cell integrity in <it>myo1Δ </it>strains.</p

Reporte del proyecto: Planeación jurídica para prevención de riesgos de empresas tecnológicas

Documento que describe el trabajo realizado en asesoria a las empresas del Parque Tecnológico del ITESO, por cuestiones de confidencialidad se suprime la información de las empresas y se registra sin anexos.ITESO, A.C

Histograms derived from Gene Set Enrichment Analysis for categories with a corrected p-value ≤ 0

<p><b>Copyright information:</b></p><p>Taken from "Global mRNA expression analysis in myosin II deficient strains of reveals an impairment of cell integrity functions"</p><p>http://www.biomedcentral.com/1471-2164/9/34</p><p>BMC Genomics 2008;9():34-34.</p><p>Published online 23 Jan 2008</p><p>PMCID:PMC2253530.</p><p></p>0004. A) Density versus t-value plots for protein biogenesis, stress response, unknown, carbohydrate metabolism, and RNA processing categories. Red lines represent the distribution of genes of a specific category in the array. Black lines represent the distribution of all genes in the array. B) t-value versus A-value plots for protein biogenesis, stress response, unknown, carbohydrate metabolism, and RNA processing categories. Red dots represent the genes of a specific category in the array. Black dots represent the distribution of all genes in the array. The cutoff for a significant category is based on a p-value calculated after 10,000 permutations and then a corrected p-value was calculated using the Bonferroni correction. See Methods section for details

Can Chlorophyll a Fluorescence and Photobleaching Be a Stress Signal under Abiotic Stress in Vigna unguiculata L.?

Greenhouse gas emissions continue raising the planet&rsquo;s temperature by 1.5 &deg;C since the industrial age, while the world population growth rate is 1.1%. So, studies aimed at food security and better land use are welcomed. In this paradigm, we choose Vigna unguiculata to test how it would behave in the face of severe abiotic stresses, such as drought and salt stress. This study shows that under abiotic stresses V. unguiculata tries to overcome the stress by emitting chlorophyll a fluorescence and promoting photobleaching. Thus, fewer photons are directed to photosystem I, to generate lethal reactive oxygen species. The antioxidant system showed a high activity in plants submitted to drought stress but fell in salt-stressed plants. Thus, the reductor power not dissipated by fluorescence or heat was captured and converted into hydrogen peroxide (H2O2) which was 2.2-fold higher in salt-stressed V. unguiculata plants. Consequently, the malondialdehyde (MDA) increased in all treatment. Compiling all data, we can argue that the rapid extinguishing of chlorophyll a fluorescence, mainly in non-photochemical quenching and heat can be an indicator of stress as a first defense system, while the H2O2 and MDA accumulation would be considered biochemical signals for plant defenses or plant injuries

Can Chlorophyll a Fluorescence and Photobleaching Be a Stress Signal under Abiotic Stress in <i>Vigna unguiculata</i> L.?

Greenhouse gas emissions continue raising the planet’s temperature by 1.5 °C since the industrial age, while the world population growth rate is 1.1%. So, studies aimed at food security and better land use are welcomed. In this paradigm, we choose Vigna unguiculata to test how it would behave in the face of severe abiotic stresses, such as drought and salt stress. This study shows that under abiotic stresses V. unguiculata tries to overcome the stress by emitting chlorophyll a fluorescence and promoting photobleaching. Thus, fewer photons are directed to photosystem I, to generate lethal reactive oxygen species. The antioxidant system showed a high activity in plants submitted to drought stress but fell in salt-stressed plants. Thus, the reductor power not dissipated by fluorescence or heat was captured and converted into hydrogen peroxide (H2O2) which was 2.2-fold higher in salt-stressed V. unguiculata plants. Consequently, the malondialdehyde (MDA) increased in all treatment. Compiling all data, we can argue that the rapid extinguishing of chlorophyll a fluorescence, mainly in non-photochemical quenching and heat can be an indicator of stress as a first defense system, while the H2O2 and MDA accumulation would be considered biochemical signals for plant defenses or plant injuries