The DEAD-Box RNA Helicase Ded1p Affects and Accumulates in<i>Saccharomyces cerevisiae</i>P-Bodies

Beckham, Carla; Hilliker, Angela K.; Cziko, Anne-Marie; Noueiry, Amine; Ramaswami, Mani; Parker, Roy

doi:10.1091/mbc.e07-09-0954

Cited by 106 publications

(119 citation statements)

References 55 publications

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“…RCK/p54 family members have an interesting mechanism of transcriptional regulation in that they act to recruit mRNA transcripts to cytoplasmic P-bodies for degradation via a CCR4-dependent mechanism of decapping and deadenylation followed by 3Ј-5Ј degradation (21). In the present study, RNA immunoprecipitation of an epitope-tagged Vad1 followed by microarray identified MF␣ transcripts as direct targets within a set of C. neoformans genes.…”

mentioning

confidence: 57%

Mating Pheromone in Cryptococcus neoformans Is Regulated by a Transcriptional/Degradative “Futile” Cycle

Park

Panepinto

Shin

et al. 2010

Journal of Biological Chemistry

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Sexual reproduction in fungi requires induction of signaling pheromones within environments that are conducive to mating. The fungus Cryptococcus neoformans is currently the fourth greatest cause of infectious death in regions of Africa and undergoes mating in phytonutrient-rich environments to create spores with infectious potential. Here we show that under conditions where sexual development is inhibited, a ϳ17-fold excess of MF␣ pheromone transcript is synthesized and then degraded by a DEAD box protein, Vad1, resulting in low steady state transcript levels. Transfer to mating medium or deletion of the VAD1 gene resulted in high level accumulation of MF␣ transcripts and enhanced mating, acting in concert with the matingrelated HOG1 pathway. We then investigated whether the high metabolic cost of this apparently futile transcriptional cycle could be justified by a more rapid induction of mating. Maintenance of Vad1 activity on inductive mating medium by constitutive expression resulted in repressed levels of MF␣ that did not prevent but rather prolonged the time to successful mating from 5-6 h to 15 h (p < 0.0001). In sum, these data suggest that VAD1 negatively regulates the sexual cell cycle via degradation of constitutive high levels of MF␣ transcripts in a synthetic/ degradative cycle, providing a mechanism of mRNA induction for time-critical cellular events, such as mating induction.To initiate sexual development, fungi produce signaling pheromones to indicate their presence and their mating compatibility. Within their natural environment on environmental surfaces, successful mating requires a close physical association that is easily disturbed for non-motile organisms, such as yeast, suggesting that rapid induction might improve the chances for successful reproduction. Induction of mating requires pheromone production and has been most extensively studied in the model ascomycete, Saccharomyces cerevisiae, where the production of mating factor precursors is followed by post-translational modifications to yield active pheromones. Local proximity of compatible yeast cells results in pheromone binding to a cognate heterotrimeric G-protein-coupled receptor on cells of the opposite mating type, followed by activation of a mitogen-activated protein kinase (MAPK) cascade that leads to cell cycle arrest followed by cell fusion and ascospore development (1). After cell fusion, compatibility of the two mating partners is confirmed intracellularly by two MAT-encoded regulatory transcription factors; in ascomycota, the MAT

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mentioning

confidence: 57%

Mating Pheromone in Cryptococcus neoformans Is Regulated by a Transcriptional/Degradative “Futile” Cycle

Park

Panepinto

Shin

et al. 2010

Journal of Biological Chemistry

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“…This observation may be explained by redundant processing helicases in the Figure 2.-Orb2, poly-A binding protein (PABP), Rm62/Dmp68, and Sm proteins are present on dFMR1-containing foci in neurites of cultured Drosophila primary neurons. Neurites of dissociated and cultured larval neurons contain distinct FMR1-containing mRNPs that also contain several molecules involved in translational control (Barbee et al 2006;Beckham et al 2008;Kwak et al 2008). These particles visualized in processes of motor neuron expressing dFMR1-YFP (from C380Gal4; ChaGal80; UASdfmr1-YFP larvae) also contain Orb2 (A-C), PABP (D-F), Rm62 (G-I), and Sm ( J-L) proteins.…”

Section: Resultsmentioning

confidence: 99%

Genetic Modifiers ofdFMR1Encode RNA Granule Components in Drosophila

Cziko¹,

McCann

Howlett³

et al. 2009

Genetics

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Mechanisms of neuronal mRNA localization and translation are of considerable biological interest. Spatially regulated mRNA translation contributes to cell-fate decisions and axon guidance during development, as well as to long-term synaptic plasticity in adulthood. The Fragile-X Mental Retardation protein (FMRP/dFMR1) is one of the best-studied neuronal translational control molecules and here we describe the identification and early characterization of proteins likely to function in the dFMR1 pathway. Induction of the dFMR1 in sevenless-expressing cells of the Drosophila eye causes a disorganized (rough) eye through a mechanism that requires residues necessary for dFMR1/FMRP's translational repressor function. Several mutations in dco, orb2, pAbp, rm62, and smD3 genes dominantly suppress the sev-dfmr1 rough-eye phenotype, suggesting that they are required for dFMR1-mediated processes. The encoded proteins localize to dFMR1-containing neuronal mRNPs in neurites of cultured neurons, and/or have an effect on dendritic branching predicted for bona fide neuronal translational repressors. Genetic mosaic analyses indicate that dco, orb2, rm62, smD3, and dfmr1 are dispensable for translational repression of hid, a microRNA target gene, known to be repressed in wing discs by the bantam miRNA. Thus, the encoded proteins may function as miRNA-and/or mRNA-specific translational regulators in vivo.

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“…The former is thought to be involved in translation (68 -71) and in mRNA storage in cytoplasmic processing bodies (P-bodies) (72). The latter was isolated as a differentially expressed cDNA, noticeably more abundant in artificially aged but viable seeds (73), relative to un-aged seeds just after the completion of germination of both groups (axis ϳ0.5 cm long).…”

Section: Discussionmentioning

confidence: 99%

Substrates of the Arabidopsis thaliana Protein Isoaspartyl Methyltransferase 1 Identified Using Phage Display and Biopanning

Chen

Nayak

Majee

et al. 2010

Journal of Biological Chemistry

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The role of protein isoaspartyl methyltransferase (PIMT) in repairing a wide assortment of damaged proteins in a host of organisms has been inferred from the affinity of the enzyme for isoaspartyl residues in a plethora of amino acid contexts. The identification of PIMT target proteins in plant seeds, where the enzyme is highly active and proteome long-lived, has been hindered by large amounts of isoaspartate-containing storage proteins. Mature seed phage display libraries circumvented this problem. Inclusion of the PIMT co-substrate, S-adenosylmethionine (AdoMet), during panning permitted PIMT to retain aged phage in greater numbers than controls lacking co-substrate or when PIMT protein binding was poisoned with S-adenosyl homocysteine. After four rounds, phage titer plateaued in AdoMet-containing pans, whereas titer declined in both controls. This strategy identified 17 in-frame PIMT target proteins, including a cupin-family protein similar to those identified previously using on-blot methylation. All recovered phage had at least one susceptible Asp or Asn residue. Five targets were recovered independently. Two in-frame targets were produced in Escherichia coli as recombinant proteins and shown by onblot methylation to acquire isoAsp, becoming a PIMT target. Both gained isoAsp rapidly in solution upon thermal insult. Mutant analysis of plants deficient in any of three in-frame PIMT targets resulted in demonstrable phenotypes. An overrepresentation of clones encoding proteins involved in protein production suggests that the translational apparatus comprises a subgroup for which PIMT-mediated repair is vital for orthodox seed longevity. Impaired PIMT activity would hinder protein function in these targets, possibly resulting in poor seed performance.

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The DEAD-Box RNA Helicase Ded1p Affects and Accumulates inSaccharomyces cerevisiaeP-Bodies

Cited by 106 publications

References 55 publications

Mating Pheromone in Cryptococcus neoformans Is Regulated by a Transcriptional/Degradative “Futile” Cycle

Mating Pheromone in Cryptococcus neoformans Is Regulated by a Transcriptional/Degradative “Futile” Cycle

Genetic Modifiers ofdFMR1Encode RNA Granule Components in Drosophila

Substrates of the Arabidopsis thaliana Protein Isoaspartyl Methyltransferase 1 Identified Using Phage Display and Biopanning

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