Reconsidering Movement of Eukaryotic mRNAs Between Polysomes and P-bodies
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae Sigma1278b
SUBMITTER: Joshua Arribere
PROVIDER: E-GEOD-31393 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:Cell survival in changing environments requires appropriate regulation of gene expression, including post-transcriptional gene regulatory mechanisms. Based on reporter gene studies in glucose-starved yeast, it was proposed that translationally silenced eukaryotic mRNAs accumulate in P-bodies and can return to active translation. We present evidence contradicting the notion that this model is a widespread and general phenomenon. First, genome-wide measurements of mRNA abundance, translation, and ribosome occupancy following glucose withdrawal show that most mRNAs are lost from the cell coincident with their loss from polysomes. Second, only a very limited sub-population of translationally repressed transcripts, comprising fewer than 400 genes, can be reactivated for translation upon glucose re-addition in the absence of new transcription. This highly selective post-transcriptional regulation could be a mechanism for cells to minimize the energetic costs of reversing gene-regulatory decisions in rapidly changing environments by transiently preserving a pool of transcripts whose translation is rate-limiting for growth. Sigma 1278b yeast were grown to OD600=1.0-1.1 in YPD in baffled flasks at 30C with vigorous shaking. Cells were treated with thiolutin to a final concentration of 3ug/mL, harvested by centrifugation, and resuspended in pre-warmed YPA medium lacking glucose. Cells were returned to 30C for shaking for 10 minutes. For the refed samples, glucose was added to a final concentration of 2% and samples were taken after 5 minutes. Polysome preparation and RNA isolation were as described in Experimental Procedues. A common RNA sample, polysomal RNA from cells grown in YPD, was used for one channel of each array.
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Project description:Aneuploidy is a hallmark of tumor cells and yet the precise relationship between aneuploidy and a cell’s proliferative ability, or cellular fitness, has remained elusive. In this study we have combined a detailed analysis of aneuploid clones isolated from laboratory-evolved populations of Saccharomyces cerevisiae with a systematic, genome-wide screen for the fitness effects of telomeric amplifications to address the relationship between aneuploidy and cellular fitness. We found that aneuploid clones rise to high population frequencies in nutrient-limited evolution experiments and show increased fitness relative to wild-type. Direct competition experiments confirmed that three out of four aneuploid events isolated from evolved populations were themselves sufficient to improve fitness. To expand the scope beyond this small number of exemplars, we created a genome-wide collection of >1,800 diploid yeast strains each containing a different telomeric amplicon (Tamp) ranging in size from 0.4 to 1,000kb. Using pooled competition experiments in nutrient-limited chemostats followed by high-throughput sequencing of strain-identifying barcodes, we determined the fitness effects of these >1,800 Tamps under three different conditions. Our data revealed that the fitness landscape explored by telomeric amplifications is much broader than that explored by single-gene amplifications. As also observed in the evolved clones, we found the fitness effects of most Tamps to be condition specific with a minority showing common effects in all three conditions. By integrating our data with previous work that examined the fitness effects of single-gene amplifications genome wide, we found that a small number of genes within each Tamp are centrally responsible for each Tamp’s fitness effects. Our genome-wide Tamp screen confirmed that telomeric amplifications identified in laboratory-evolved populations generally increased fitness. Our results show that Tamps are mutations that produce large, typically condition-dependent changes in fitness that are important drivers of increased fitness in asexually evolving populations. Each of these arrays is a Comparative Genomic Hybridization experiment to detect copy number differences between a reference strain and a strain of interest.
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Project description:Microarray data for study "The master regulators AphA and LuxR control the Vibrio harveyi quorum-sensing regulon: analysis of their individual and combined effects". Bacteria use a chemical communication process called quorum sensing to control transitions between individual and group behaviors. In the Vibrio harveyi quorum-sensing circuit, two master transcription factors AphA and LuxR coordinate the quorum-sensing response. Here we show that AphA regulates 167 genes, LuxR regulates 625 genes, and they co-regulate 77 genes. LuxR strongly controls genes both at low-cell-density and high-cell-density, suggesting it is the major quorum-sensing regulator. By contrast, AphA is absent at high-cell-density, and acts to fine-tune quorum-sensing gene expression at low-cell-density. We examined two loci as case studies of co-regulation by AphA and LuxR. First, AphA and LuxR directly regulate expression of the genes encoding the quorum regulatory small RNAs Qrr2, Qrr3, and Qrr4, the consequence of which is a specifically timed transition between the individual and the group lifestyle. Second, AphA and LuxR repress type III secretion system genes but at different times and to different extents. The consequence of this regulation is that type III secretion is restricted to a peak at mid-cell-density. Thus, asymmetric production of AphA and LuxR coupled with differences in their strength and timing of target gene regulation generates a precise temporal pattern of gene expression. Triplicate biological samples of Vibrio harveyi strains STR416 and JV55 were hybridized to Agilent arrays (Amadid design ID: 021087), and one experiment was a control dye-swap, for a total of four experiments in this array set.
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Project description:Microarray data for study "The master regulators AphA and LuxR control the Vibrio harveyi quorum-sensing regulon: analysis of their individual and combined effects". Bacteria use a chemical communication process called quorum sensing to control transitions between individual and group behaviors. In the Vibrio harveyi quorum-sensing circuit, two master transcription factors AphA and LuxR coordinate the quorum-sensing response. Here we show that AphA regulates 167 genes, LuxR regulates 625 genes, and they co-regulate 77 genes. LuxR strongly controls genes both at low-cell-density and high-cell-density, suggesting it is the major quorum-sensing regulator. By contrast, AphA is absent at high-cell-density, and acts to fine-tune quorum-sensing gene expression at low-cell-density. We examined two loci as case studies of co-regulation by AphA and LuxR. First, AphA and LuxR directly regulate expression of the genes encoding the quorum regulatory small RNAs Qrr2, Qrr3, and Qrr4, the consequence of which is a specifically timed transition between the individual and the group lifestyle. Second, AphA and LuxR repress type III secretion system genes but at different times and to different extents. The consequence of this regulation is that type III secretion is restricted to a peak at mid-cell-density. Thus, asymmetric production of AphA and LuxR coupled with differences in their strength and timing of target gene regulation generates a precise temporal pattern of gene expression. Triplicate biological samples of Vibrio harveyi strains KM810 and JV55 were hybridized to Agilent arrays (Amadid design ID: 021087), and one experiment was a control dye-swap, for a total of four experiments in this array set. KM810 contains a luxO D47E phosphomimic allele and a deletion in luxR; JV55 contains a luxO D47E phosphomimic allele and deletions in luxR and aphA.
2013-02-20 | E-GEOD-44196 | biostudies-arrayexpress
Project description:Microarray data for study "The master regulators AphA and LuxR control the Vibrio harveyi quorum-sensing regulon: analysis of their individual and combined effects". Bacteria use a chemical communication process called quorum sensing to control transitions between individual and group behaviors. In the Vibrio harveyi quorum-sensing circuit, two master transcription factors AphA and LuxR coordinate the quorum-sensing response. Here we show that AphA regulates 167 genes, LuxR regulates 625 genes, and they co-regulate 77 genes. LuxR strongly controls genes both at low-cell-density and high-cell-density, suggesting it is the major quorum-sensing regulator. By contrast, AphA is absent at high-cell-density, and acts to fine-tune quorum-sensing gene expression at low-cell-density. We examined two loci as case studies of co-regulation by AphA and LuxR. First, AphA and LuxR directly regulate expression of the genes encoding the quorum regulatory small RNAs Qrr2, Qrr3, and Qrr4, the consequence of which is a specifically timed transition between the individual and the group lifestyle. Second, AphA and LuxR repress type III secretion system genes but at different times and to different extents. The consequence of this regulation is that type III secretion is restricted to a peak at mid-cell-density. Thus, asymmetric production of AphA and LuxR coupled with differences in their strength and timing of target gene regulation generates a precise temporal pattern of gene expression. Triplicate biological samples of Vibrio harveyi strains STR415 and JV54 were hybridized to Agilent arrays (Amadid design ID: 021087), and one experiment was a control dye-swap, for a total of four experiments in this array set.
2013-02-20 | E-GEOD-44199 | biostudies-arrayexpress