Reconsidering Movement of Eukaryotic mRNAs Between Polysomes and P-bodies
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PROVIDER: PRJNA145877 | ENA |
REPOSITORIES: ENA
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Project description:Eukaryotic cells contain nontranslating messenger RNA concentrated in P-bodies, which are sites where the mRNA can be decapped and degraded. We present evidence that mRNA molecules within yeast P-bodies can also return to translation. First, inhibiting delivery of new mRNAs to P-bodies leads to their disassembly independent of mRNA decay. Second, P-bodies decline in a translation initiation-dependent manner during stress recovery. Third, reporter mRNAs concentrate in P-bodies when translation initiation is blocked and resume translation and exit P-bodies when translation is restored. Fourth, stationary phase yeast have large P-bodies containing mRNAs that reenter translation when growth resumes. The reciprocal movement of mRNAs between polysomes and P-bodies is likely to be important in the control of mRNA translation and degradation. Moreover, the presence of related proteins in P-bodies and maternal mRNA storage granules suggests this mechanism is widely adapted for mRNA storage.
| S-EPMC1863069 | biostudies-literature
Project description:Cell survival in changing environments requires appropriate regulation of gene expression, including posttranscriptional regulatory mechanisms. From 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 reversible storage of nontranslating mRNAs is a widespread and general phenomenon. First, genome-wide measurements of mRNA abundance, translation, and ribosome occupancy after glucose withdrawal show that most mRNAs are depleted from the cell coincident with their depletion from polysomes. Second, only a limited subpopulation of translationally repressed transcripts, comprising fewer than 400 genes, can be reactivated for translation upon glucose readdition in the absence of new transcription. This highly selective posttranscriptional 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.
| S-EPMC3240842 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2011-09-05 | GSE31393 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE31220: Polysome-associated mRNA levels upon glucose repletion GSE31392: Timecourse of total and polysome-associated mRNA levels post glucose deprivation Refer to individual Series
2011-09-04 | E-GEOD-31393 | biostudies-arrayexpress
Project description:Although most eukaryotic mRNAs need a functional cap binding complex eIF4F for efficient 5' end- dependent scanning to initiate translation, picornaviral, hepatitis C viral, and a few cellular RNAs have been shown to be translated by internal ribosome entry, a mechanism that can operate in the presence of low levels of functional eIF4F. To identify cellular mRNAs that can be translated when eIF4F is depleted or in low abundance and that, therefore, may contain internal ribosome entry sites, mRNAs that remained associated with polysomes were isolated from human cells after infection with poliovirus and were identified by using a cDNA microarray. Approximately 200 of the 7000 mRNAs analyzed remained associated with polysomes under these conditions. Among the gene products encoded by these polysome-associated mRNAs were immediate-early transcription factors, kinases, and phosphatases of the mitogen-activated protein kinase pathways and several protooncogenes, including c-myc and Pim-1. In addition, the mRNA encoding Cyr61, a secreted factor that can promote angiogenesis and tumor growth, was selectively mobilized into polysomes when eIF4F concentrations were reduced, although its overall abundance changed only slightly. Subsequent tests confirmed the presence of internal ribosome entry sites in the 5' noncoding regions of both Cyr61 and Pim-1 mRNAs. Overall, this study suggests that diverse mRNAs whose gene products have been implicated in a variety of stress responses, including inflammation, angiogenesis, and the response to serum, can use translational initiation mechanisms that require little or no intact cap binding protein complex eIF4F.
2005-06-24 | E-SMDB-59 | biostudies-arrayexpress
Project description:Identification of eukaryotic mRNAs that are translated at reduced cap binding complex eIF4F concentrations using a cDNA microarray. Although most eukaryotic mRNAs need a functional cap binding complex eIF4F for efficient 5' end-dependent scanning to initiate translation, picornaviral, hepatitis C viral, and a few cellular RNAs have been shown to be translated by internal ribosome entry, a mechanism that can operate in the presence of low levels of functional eIF4F. To identify cellular mRNAs that can be translated when eIF4F is depleted or in low abundance and that, therefore, may contain internal ribosome entry sites, mRNAs that remained associated with polysomes were isolated from human cells after infection with poliovirus and were identified by using a cDNA microarray. Approximately 200 of the 7000 mRNAs analyzed remained associated with polysomes under these conditions. Among the gene products encoded by these polysome-associated mRNAs were immediate-early transcription factors, kinases, and phosphatases of the mitogen-activated protein kinase pathways and several protooncogenes, including c-myc and Pim-1. In addition, the mRNA encoding Cyr61, a secreted factor that can promote angiogenesis and tumor growth, was selectively mobilized into polysomes when eIF4F concentrations were reduced, although its overall abundance changed only slightly. Subsequent tests confirmed the presence of internal ribosome entry sites in the 5' noncoding regions of both Cyr61 and Pim-1 mRNAs. Overall, this study suggests that diverse mRNAs whose gene products have been implicated in a variety of stress responses, including inflammation, angiogenesis, and the response to serum, can use translational initiation mechanisms that require little or no intact cap binding protein complex eIF4F. This study is described more fully in Johannes G et al.(1999) Proc Natl Acad Sci U S A 96:13118-23.
2002-06-27 | E-GEOD-62 | biostudies-arrayexpress
Project description:Identification of eukaryotic mRNAs that are translated at reduced cap binding complex eIF4F concentrations using a cDNA microarray. Although most eukaryotic mRNAs need a functional cap binding complex eIF4F for efficient 5' end-dependent scanning to initiate translation, picornaviral, hepatitis C viral, and a few cellular RNAs have been shown to be translated by internal ribosome entry, a mechanism that can operate in the presence of low levels of functional eIF4F. To identify cellular mRNAs that can be translated when eIF4F is depleted or in low abundance and that, therefore, may contain internal ribosome entry sites, mRNAs that remained associated with polysomes were isolated from human cells after infection with poliovirus and were identified by using a cDNA microarray. Approximately 200 of the 7000 mRNAs analyzed remained associated with polysomes under these conditions. Among the gene products encoded by these polysome-associated mRNAs were immediate-early transcription factors, kinases, and phosphatases of the mitogen-activated protein kinase pathways and several protooncogenes, including c-myc and Pim-1. In addition, the mRNA encoding Cyr61, a secreted factor that can promote angiogenesis and tumor growth, was selectively mobilized into polysomes when eIF4F concentrations were reduced, although its overall abundance changed only slightly. Subsequent tests confirmed the presence of internal ribosome entry sites in the 5' noncoding regions of both Cyr61 and Pim-1 mRNAs. Overall, this study suggests that diverse mRNAs whose gene products have been implicated in a variety of stress responses, including inflammation, angiogenesis, and the response to serum, can use translational initiation mechanisms that require little or no intact cap binding protein complex eIF4F. This study is described more fully in Johannes G et al.(1999) Proc Natl Acad Sci U S A 96:13118-23. Keywords: other
2002-06-27 | GSE62 | GEO
Project description:Gametes rely heavily on post-transcriptional control mechanisms to regulate their differentiation. In eggs, the storage and selective temporal activation of maternal mRNAs is essential for normal development. In the male, transcription ceases during spermiogenesis necessitating the post-transcriptional regulation of many paternal mRNAs required for spermatid differentiation and spermatozoan function. Messenger RNAs that are being actively translated form polysomes. whereas translationally inactive mRNAs are often sequestered in ribonucleoproteins (RNPs). Here we combine polysome display and microarray analyses of RNP and polysome fractions of testes from prepuberal and adult mice to characterize the translation state of individual mRNAs as spermatogenesis proceeds.. Consistent with published reports, many post-meiotic mRNAs known to be translationally delayed shift from the RNPs into the polysomes, confirming the validity of this approach. In addition, based upon the criterion of movement from RNPs to polysomes, we detect another 742 mouse testicular genes showing dramatic shifts between RNPs and polysomes. One sub-group of 35 genes including the known translationally delayed Pgk2, are initially transcribed and translationally repressed in meiotic spermatocytes, and translated post-meiotically. This high-through-put approach defines the changing translation patterns of a large number of genes as male germ cells differentiate and identifies a new group of post-transcriptionally regulated meiotic transcripts for future study. Keywords: time course
2006-05-15 | GSE4711 | GEO
Project description:Translation of localized mRNAs serves to regulate specific sites of protein synthesis and its functional activity, whereas translationally inhibited and untranslated mRNAs are compartmentalized for degradation or storage, with no recognized functional role. Here, however, we unexpectedly discover a group of functional, untranslated mRNA sequences that localize to integrin focal adhesions (FAs), dynamic multiprotein assemblies that govern cell movement. We show that specific mRNA sequences associate with native or mature FA functional states via messenger ribonucleoprotein (mRNP) complexes with the RNA and FA binding protein G3BP1, functioning to regulate cell migration. Mechanistically, the dimerizing propensity of the mRNA in G3BP1 mRNPs directly regulates FA protein function. Self-dimerizing mRNA sequences form large branched G3BP1 mRNPs, reducing FA protein turnover and extending adhesion lifetimes, inhibiting cell migration. In contrast, low self-dimerization promotes small more spheric G3BP1 mRNPs, facilitating FA complex dissolution and enhancing cell migration behaviors. Our findings define a previously unknown role for cytoplasmic mRNAs, challenging the notion that mRNAs are solely coding molecules and shedding light on their regulatory functions.
2024-04-20 | GSE246955 | GEO
Project description:Translation of localized mRNAs serves to regulate specific sites of protein synthesis and its functional activity, whereas translationally inhibited and untranslated mRNAs are compartmentalized for degradation or storage, with no recognized functional role. Here, however, we unexpectedly discover a group of functional, untranslated mRNA sequences that localize to integrin focal adhesions (FAs), dynamic multiprotein assemblies that govern cell movement. We show that specific mRNA sequences associate with native or mature FA functional states via messenger ribonucleoprotein (mRNP) complexes with the RNA and FA binding protein G3BP1, functioning to regulate cell migration. Mechanistically, the dimerizing propensity of the mRNA in G3BP1 mRNPs directly regulates FA protein function. Self-dimerizing mRNA sequences form large branched G3BP1 mRNPs, reducing FA protein turnover and extending adhesion lifetimes, inhibiting cell migration. In contrast, low self-dimerization promotes small more spheric G3BP1 mRNPs, facilitating FA complex dissolution and enhancing cell migration behaviors. Our findings define a previously unknown role for cytoplasmic mRNAs, challenging the notion that mRNAs are solely coding molecules and shedding light on their regulatory functions.
2024-04-20 | GSE246499 | GEO