scholarly journals Translational Control of Canonical and Non-Canonical Translation Initiation Factors at the Sea Urchin Egg to Embryo Transition

2019 ◽  
Vol 20 (3) ◽  
pp. 626
Author(s):  
Héloïse Chassé ◽  
Sandrine Boulben ◽  
Patrick Cormier ◽  
Julia Morales
Keyword(s):  
Early Development ◽  
Sea Urchin ◽  
Translation Initiation ◽  
Translational Control ◽  
Translational Regulation ◽  
Sea Urchins ◽  
Embryonic Cell ◽  
Scaffolding Protein ◽  
Initiation Factors ◽  
The Impact

Sea urchin early development is a powerful model to study translational regulation under physiological conditions. Fertilization triggers an activation of the translation machinery responsible for the increase of protein synthesis necessary for the completion of the first embryonic cell cycles. The cap-binding protein eIF4E, the helicase eIF4A and the large scaffolding protein eIF4G are assembled upon fertilization to form an initiation complex on mRNAs involved in cap-dependent translation initiation. The presence of these proteins in unfertilized and fertilized eggs has already been demonstrated, however data concerning the translational status of translation factors are still scarce. Using polysome fractionation, we analyzed the impact of fertilization on the recruitment of mRNAs encoding initiation factors. Strikingly, whereas the mRNAs coding eIF4E, eIF4A, and eIF4G were not recruited into polysomes at 1 h post-fertilization, mRNAs for eIF4B and for non-canonical initiation factors such as DAP5, eIF4E2, eIF4E3, or hnRNP Q, are recruited and are differentially sensitive to the activation state of the mechanistic target of rapamycin (mTOR) pathway. We discuss our results suggesting alternative translation initiation in the context of the early development of sea urchins.

The impact of CO 2 -driven ocean acidification on early development and calcification in the sea urchin Strongylocentrotus intermedius

2016 ◽  
Vol 112 (1-2) ◽  
pp. 291-302 ◽  
Author(s):  
Yaoyao Zhan ◽  
Wanbin Hu ◽  
Weijie Zhang ◽  
Minbo Liu ◽  
Lizhu Duan ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Early Development ◽  
Sea Urchin ◽  
Strongylocentrotus Intermedius ◽  
The Impact

Counterproductive transcriptional and translational regulation of elongation factor 1-α synthesis during early development in sea urchins

1990 ◽  
Vol 142 (2) ◽  
pp. 486-488 ◽  
Author(s):  
Margaret Truschel Peeler ◽  
Leslie Kelso-Winemiller ◽  
Ming-Fan Wu ◽  
James K. Skipper ◽  
Matthew M. Winkler
Keyword(s):  
Early Development ◽  
Translational Regulation ◽  
Sea Urchins ◽  
Elongation Factor ◽  
Elongation Factor 1 ◽  
Transcriptional And Translational Regulation

Effect of unidirectional water currents on displacement behaviour of the green sea urchin Strongylocentrous droebachiensis

2013 ◽  
Vol 93 (7) ◽  
pp. 1923-1928 ◽  
Author(s):  
Bryan L. Morse ◽  
Heather L. Hunt
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Flow Speed ◽  
Strongylocentrotus Droebachiensis ◽  
Movement Speed ◽  
Water Current ◽  
Flume Experiments ◽  
Water Currents ◽  
Green Sea Urchin ◽  
The Impact

Sea urchins can have important ecological effects on benthic communities through their aggregation and feeding behaviour. Urchin movement has been demonstrated to be negatively affected by wave action, but the impact of unidirectional tidal currents on urchin movement has not been investigated. This study examines the effect of unidirectional water velocity on the direction of displacement and movement rate of the green sea urchin, Strongylocentrotus droebachiensis. In laboratory flume experiments there was a clear effect of water currents on the displacement of sea urchins. At speeds ≤30 cm s−1 urchins moved across the current in a downstream direction, but at speeds of ≥36 cm s−1 the urchins switched directions by more than 90° and moved across the current in an upstream direction. There was a significant effect of flow speed on urchin movement speed, with urchin movement speed decreasing as water current speed increased.

scholarly journals The impact of ocean acidification and warming on the skeletal mechanical properties of the sea urchin Paracentrotus lividus from laboratory and field observations

2015 ◽  
Vol 73 (3) ◽  
pp. 727-738 ◽  
Author(s):  
Marie Collard ◽  
Samuel P. S. Rastrick ◽  
Piero Calosi ◽  
Yoann Demolder ◽  
Jean Dille ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Laboratory Experiment ◽  
Young’S Modulus ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Young's Modulus ◽  
Paracentrotus Lividus ◽  
Low Ph ◽  
Fracture Force ◽  
The Impact

Abstract Increased atmospheric CO2 concentration is leading to changes in the carbonate chemistry and the temperature of the ocean. The impact of these processes on marine organisms will depend on their ability to cope with those changes, particularly the maintenance of calcium carbonate structures. Both a laboratory experiment (long-term exposure to decreased pH and increased temperature) and collections of individuals from natural environments characterized by low pH levels (individuals from intertidal pools and around a CO2 seep) were here coupled to comprehensively study the impact of near-future conditions of pH and temperature on the mechanical properties of the skeleton of the euechinoid sea urchin Paracentrotus lividus. To assess skeletal mechanical properties, we characterized the fracture force, Young's modulus, second moment of area, material nanohardness, and specific Young's modulus of sea urchin test plates. None of these parameters were significantly affected by low pH and/or increased temperature in the laboratory experiment and by low pH only in the individuals chronically exposed to lowered pH from the CO2 seeps. In tidal pools, the fracture force was higher and the Young's modulus lower in ambital plates of individuals from the rock pool characterized by the largest pH variations but also a dominance of calcifying algae, which might explain some of the variation. Thus, decreases of pH to levels expected for 2100 did not directly alter the mechanical properties of the test of P. lividus. Since the maintenance of test integrity is a question of survival for sea urchins and since weakened tests would increase the sea urchins' risk of predation, our findings indicate that the decreasing seawater pH and increasing seawater temperature expected for the end of the century should not represent an immediate threat to sea urchins vulnerability.

scholarly journals Cell-free translation systems prepared from starfish oocytes faithfully reflect in vivo activity; mRNA and initiation factors stimulate supernatants from immature oocytes.

1990 ◽  
Vol 1 (13) ◽  
pp. 1057-1067 ◽  
Author(s):  
Z Xu ◽  
M B Hille
Keyword(s):  
Translational Control ◽  
Translational Regulation ◽  
High Capacity ◽  
Meiotic Maturation ◽  
Immature Oocytes ◽  
Initiation Factors ◽  
Initiation Of Translation ◽  
Free Translation ◽  
Translation Systems

Meiotic maturation stimulates a change in the translation of stored mRNAs: mRNAs encoding proteins needed for growth of oocytes are translated before meiotic maturation, whereas those encoding proteins required for cleavage are translated after meiotic maturation. Studies of translational regulation during meiotic maturation have been limited by the lack of translationally active cell-free supernatants. Starfish oocytes are ideal for preparing cell-free translation systems because experimental application of the hormone 1-methyladenine induces their maturation, synchronizing meiosis. We have prepared such systems from both immature and mature oocytes of starfish. Changes in protein synthesis rates and the specificity of proteins synthesized in these cell-free translation supernatants mimic those seen in vivo. Supernatants both from immature and mature oocytes have a high capacity to initiate new translation because 90% of the proteins made are newly initiated from mRNAs. Cell-free supernatants from mature oocytes have a much higher rate of initiation of translation than those from immature oocytes and use the 43S preinitiation complexes more efficiently in initiation of translation. Similarly, we have shown that mRNAs and initiation factors are rate limiting in cell-free translation systems prepared from immature oocytes. In addition, cell-free translation systems prepared from immature oocytes are only slightly, if at all, inhibitory to cell-free translation systems from mature oocytes. Thus, soluble inhibitors, if they exist, are rapidly converted by cell-free supernatants from mature oocytes. The similarities between translation in our starfish cell-free translation systems and in intact oocytes suggests that the cell-free translation systems will be useful tools for further studies of maturation events and translational control during meiosis.

scholarly journals Upregulation of eIF4E, but not other translation initiation factors, in dendritic spines during memory consolidation

2021 ◽  
Author(s):  
Sofya Gindina ◽  
Benjamin Botsford ◽  
Kiriana Cowansage ◽  
Joseph LeDoux ◽  
Eric Klann ◽  
...  
Keyword(s):  
Pavlovian Conditioning ◽  
Translation Initiation ◽  
Dendritic Spines ◽  
Translational Control ◽  
Protein Targeting ◽  
Specific Protein ◽  
Control Mechanisms ◽  
Initiation Factors ◽  
Translation Initiation Factors ◽  
Transmission Electron

AbstractLocal translation can provide a rapid, spatially targeted supply of new proteins in distal dendrites to support synaptic changes that underlie learning. Learning and memory are especially sensitive to manipulations of translational control mechanisms, particularly those that target the initiation step, and translation initiation at synapses could be a means of maintaining synapse specificity during plasticity. Initiation predominantly occurs via recruitment of ribosomes to the 5’ mRNA cap by complexes of eukaryotic initiation factors (eIFs), and the interaction between eIF4E and eIF4G1 is a particularly important target of translational control pathways. Pharmacological inhibition of eIF4E-eIF4G1 binding impairs consolidation of memory for aversive Pavlovian conditioning as well as the accompanying increase in polyribosomes in the heads of dendritic spines in the lateral amygdala (LA). This is consistent with a role for initiation at synapses in memory formation, but whether eIFs are even present near synapses is unknown. To determine whether dendritic spines contain eIFs and whether eIF distribution is affected by learning, we combined immunolabeling with serial section transmission electron microscopy (ssTEM) volume reconstructions of LA dendrites after Pavlovian conditioning. Labeling for eIF4E, eIF4G1, and eIF2α – another key target of regulation – occurred in roughly half of dendritic spines, but learning effects were only found for eIF4E, which was upregulated in the heads of dendritic spines. Our results support the possibility of regulated translation initiation as a means of synapse-specific protein targeting during learning and are consistent with the model of eIF4E availability as a central point of control.

scholarly journals O-GlcNAcylation of core components of the translation initiation machinery regulates protein synthesis

2019 ◽  
Vol 116 (16) ◽  
pp. 7857-7866 ◽  
Author(s):  
Xuexia Li ◽  
Qiang Zhu ◽  
Xiaoliu Shi ◽  
Yaxian Cheng ◽  
Xueliu Li ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Protein Synthesis ◽  
Translation Initiation ◽  
Translational Control ◽  
Soft Agar ◽  
Initiation Complex ◽  
Site Specific ◽  
Initiation Factors ◽  
Key Factor ◽  
Core Components

Protein synthesis is essential for cell growth, proliferation, and survival. Protein synthesis is a tightly regulated process that involves multiple mechanisms. Deregulation of protein synthesis is considered as a key factor in the development and progression of a number of diseases, such as cancer. Here we show that the dynamic modification of proteins by O-linked β-N-acetyl-glucosamine (O-GlcNAcylation) regulates translation initiation by modifying core initiation factors eIF4A and eIF4G, respectively. Mechanistically, site-specific O-GlcNAcylation of eIF4A on Ser322/323 disrupts the formation of the translation initiation complex by perturbing its interaction with eIF4G. In addition, O-GlcNAcylation inhibits the duplex unwinding activity of eIF4A, leading to impaired protein synthesis, and decreased cell proliferation. In contrast, site-specific O-GlcNAcylation of eIF4G on Ser61 promotes its interaction with poly(A)-binding protein (PABP) and poly(A) mRNA. Depletion of eIF4G O-GlcNAcylation results in inhibition of protein synthesis, cell proliferation, and soft agar colony formation. The differential glycosylation of eIF4A and eIF4G appears to be regulated in the initiation complex to fine-tune protein synthesis. Our study thus expands the current understanding of protein synthesis, and adds another dimension of complexity to translational control of cellular proteins.

scholarly journals uORFs: Important Cis-Regulatory Elements in Plants

2020 ◽  
Vol 21 (17) ◽  
pp. 6238
Author(s):  
Ting Zhang ◽  
Anqi Wu ◽  
Yaping Yue ◽  
Yu Zhao
Keyword(s):  
Gene Expression ◽  
Translation Initiation ◽  
Translational Control ◽  
Translational Regulation ◽  
Regulatory Elements ◽  
Ribosome Profiling ◽  
Open Reading Frames ◽  
Post Translational Modification ◽  
Cis Acting ◽  
Eukaryotic Mrnas

Gene expression is regulated at many levels, including mRNA transcription, translation, and post-translational modification. Compared with transcriptional regulation, mRNA translational control is a more critical step in gene expression and allows for more rapid changes of encoded protein concentrations in cells. Translation is highly regulated by complex interactions between cis-acting elements and trans-acting factors. Initiation is not only the first phase of translation, but also the core of translational regulation, because it limits the rate of protein synthesis. As potent cis-regulatory elements in eukaryotic mRNAs, upstream open reading frames (uORFs) generally inhibit the translation initiation of downstream major ORFs (mORFs) through ribosome stalling. During the past few years, with the development of RNA-seq and ribosome profiling, functional uORFs have been identified and characterized in many organisms. Here, we review uORF identification, uORF classification, and uORF-mediated translation initiation. More importantly, we summarize the translational regulation of uORFs in plant metabolic pathways, morphogenesis, disease resistance, and nutrient absorption, which open up an avenue for precisely modulating the plant growth and development, as well as environmental adaption. Additionally, we also discuss prospective applications of uORFs in plant breeding.

scholarly journals Senescence and Longevity of Sea Urchins

Genes ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 573
Author(s):  
Yam Amir ◽  
Maayan Insler ◽  
Abram Giller ◽  
Danielle Gutman ◽  
Gil Atzmon
Keyword(s):  
Sea Urchin ◽  
Translational Regulation ◽  
Healthy Aging ◽  
Sea Urchins ◽  
Expression Patterns ◽  
Adult Life ◽  
Gene Families ◽  
Telomerase Activity ◽  
Human Longevity ◽  
Biological Aging

Sea urchins are a minor class of marine invertebrates that share genetic similarities with humans. For example, the sea urchin species Strongylocentrotus purpuratus is estimated to have 23,300 genes in which the majority of vertebrate gene families are enveloped. Some of the sea urchin species can demonstrate extreme longevity, such as Mesocentrotus franciscanus, living for well over 100 years. Comparing human to sea urchin aging suggests that the latter do not fit within the classic understanding of biological aging, as both long- and short-lived sea urchin species demonstrate negligible senescence. Sea urchins are highly regenerative organisms. Adults can regenerate external appendages and can maintain their regenerative abilities throughout life. They grow indeterminately and reproduce throughout their entire adult life. Both long- and short-lived species do not exhibit age-associated telomere shortening and display telomerase activity in somatic tissues regardless of age. Aging S. purpuratus urchins show changes in expression patterns of protein coding genes that are involved in several fundamental cellular functions such as the ubiquitin-proteasome system, signaling pathways, translational regulation, and electron transport chain. Sea urchin longevity and senescence research is a new and promising field that holds promise for the understanding of aging in vertebrates and can increase our understanding of human longevity and of healthy aging.

scholarly journals Established and Emerging Regulatory Roles of Eukaryotic Translation Initiation Factor 5B (eIF5B)

2021 ◽  
Vol 12 ◽  
Author(s):  
Prakash Amruth Raj Chukka ◽  
Stacey D. Wetmore ◽  
Nehal Thakor
Keyword(s):  
Translation Initiation ◽  
Translational Control ◽  
Translational Regulation ◽  
Eukaryotic Cell ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Eukaryotic Translation ◽  
Cellular Mrnas ◽  
Eukaryotic Translation Initiation ◽  
Initiation Stage

Translational control (TC) is one the crucial steps that dictate gene expression and alter the outcome of physiological process like programmed cell death, metabolism, and proliferation in a eukaryotic cell. TC occurs mainly at the translation initiation stage. The initiation factor eIF5B tightly regulates global translation initiation and facilitates the expression of a subset of proteins involved in proliferation, inhibition of apoptosis, and immunosuppression under stress conditions. eIF5B enhances the expression of these survival proteins to allow cancer cells to metastasize and resist chemotherapy. Using eIF5B as a biomarker or drug target could help with diagnosis and improved prognosis, respectively. To achieve these goals, it is crucial to understand the role of eIF5B in translational regulation. This review recapitulates eIF5B’s regulatory roles in the translation initiation of viral mRNA as well as the cellular mRNAs in cancer and stressed eukaryotic cells.

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