scholarly journals Translational control of gurken mRNA in Drosophila development

2016 ◽  
Author(s):  
Christopher J. Derrick ◽  
Timothy T. Weil
Keyword(s):  
Cell Fate ◽  
Translational Control ◽  
Mrna Translation ◽  
Nurse Cells ◽  
Processing Bodies ◽  
Over Expression ◽  
Egg Chambers ◽  
Key Aspects ◽  
Spatiotemporal Control

ABSTRACTLocalised mRNA translation is a widespread mechanism for targeting protein synthesis, important for cell fate, motility and pathogenesis. In Drosophila, the spatiotemporal control of gurken/TGF-α mRNA translation is required for establishing the embryonic body axes. A number of recent studies have highlighted key aspects of the mechanism of gurken mRNA translational control at the dorsoanterior corner of the mid-stage oocyte. Orb/CPEB and Wispy/GLD-2 are required for polyadenylation of gurken mRNA, but mis-localised gurken mRNA in the oocyte is not fully polyadenylated1. At the dorsoanterior corner, Orb and gurken mRNA have been shown to be enriched at the edge of Processing bodies, where translation occurs2. Over-expression of Orb in the adjacent nurse cells, where gurken mRNA is transcribed, is sufficient to cause mis-expression of Gurken protein3. In orb mutant egg chambers, reducing the activity of CK2, a Serine/Threonine protein kinase, enhances polarity defects, consistent with a phenotype relating to a mutation of a factor involved in gurken translation4. Here we show that sites phosphorylated by CK2 overlap with active Orb and with Gurken protein expression. We also consolidate the current literature into a working model for gurken mRNA translational control and review the role of kinases, cell cycle factors and polyadenylation machinery highlighting a multitude of conserved factors and mechanisms in the Drosophila egg chamber.

scholarly journals N1-acetylspermidine is a determinant of hair follicle stem cell fate

2021 ◽  
Vol 134 (9) ◽  
Author(s):  
Kira Allmeroth ◽  
Christine S. Kim ◽  
Andrea Annibal ◽  
Andromachi Pouikli ◽  
Janis Koester ◽  
...  
Keyword(s):  
Stem Cell ◽  
Hair Follicle ◽  
Cell Fate ◽  
Translational Control ◽  
Mrna Translation ◽  
Stem Cell Differentiation ◽  
Stem Cell Fate ◽  
Cell Fate Decisions ◽  
Hair Follicle Stem Cell

ABSTRACT Stem cell differentiation is accompanied by increased mRNA translation. The rate of protein biosynthesis is influenced by the polyamines putrescine, spermidine and spermine, which are essential for cell growth and stem cell maintenance. However, the role of polyamines as endogenous effectors of stem cell fate and whether they act through translational control remains obscure. Here, we investigate the function of polyamines in stem cell fate decisions using hair follicle stem cell (HFSC) organoids. Compared to progenitor cells, HFSCs showed lower translation rates, correlating with reduced polyamine levels. Surprisingly, overall polyamine depletion decreased translation but did not affect cell fate. In contrast, specific depletion of natural polyamines mediated by spermidine/spermine N1-acetyltransferase (SSAT; also known as SAT1) activation did not reduce translation but enhanced stemness. These results suggest a translation-independent role of polyamines in cell fate regulation. Indeed, we identified N1-acetylspermidine as a determinant of cell fate that acted through increasing self-renewal, and observed elevated N1-acetylspermidine levels upon depilation-mediated HFSC proliferation and differentiation in vivo. Overall, this study delineates the diverse routes of polyamine metabolism-mediated regulation of stem cell fate decisions. This article has an associated First Person interview with the first author of the paper.

scholarly journals The Role of Translation Initiation Regulation in Haematopoiesis

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Godfrey Grech ◽  
Marieke von Lindern
Keyword(s):  
Gene Expression ◽  
Translation Initiation ◽  
Translational Control ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Regulation Of Gene Expression ◽  
Mrna Translation ◽  
Translation Control ◽  
Haematological Disorders

Organisation of RNAs into functional subgroups that are translated in response to extrinsic and intrinsic factors underlines a relatively unexplored gene expression modulation that drives cell fate in the same manner as regulation of the transcriptome by transcription factors. Recent studies on the molecular mechanisms of inflammatory responses and haematological disorders indicate clearly that the regulation of mRNA translation at the level of translation initiation, mRNA stability, and protein isoform synthesis is implicated in the tight regulation of gene expression. This paper outlines how these posttranscriptional control mechanisms, including control at the level of translation initiation factors and the role of RNA binding proteins, affect hematopoiesis. The clinical relevance of these mechanisms in haematological disorders indicates clearly the potential therapeutic implications and the need of molecular tools that allow measurement at the level of translational control. Although the importance of miRNAs in translation control is well recognised and studied extensively, this paper will exclude detailed account of this level of control.

scholarly journals The Cell Fate Determinant Musashi Is Controlled Through Dynamic Protein:Protein Interactions

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A555-A555
Author(s):  
Katherine Bronson ◽  
Meenakshisundaram Balasubramaniam ◽  
Linda Hardy ◽  
Gwen V Childs ◽  
Melanie C MacNicol ◽  
...  
Keyword(s):  
Cell Fate ◽  
Oocyte Maturation ◽  
Rna Binding ◽  
Mrna Translation ◽  
Hormone Production ◽  
Target Mrna ◽  
Associated Proteins ◽  
Specific Regulation ◽  
Partner Proteins

Abstract The Musashi RNA-binding protein functions as a gatekeeper of cell maturation and plasticity through the control of target mRNA translation. It is understood that Musashi promotes stem cell self-renewal and opposes differentiation. While Musashi is best characterized as a repressor of target mRNA translation, we have shown that Musashi can activate target mRNA translation in a cell context specific manner via regulatory phosphorylation on two evolutionarily conserved C-terminal serine residues. Our recent work has found that Musashi is expressed in pituitary stem cells as well as in differentiated hormone producing cell lineages in the adult pituitary. We hypothesize that Musashi maintains cell fate plasticity in the adult pituitary to allow the gland to modulate hormone production in response to changing organismal needs. Here, we seek to understand the regulation of Musashi function. Both Musashi isoforms (Musashi1 and Musashi2) contain two RNA-recognition motifs (RRMs) that bind to specific sequences in the 3’-UTR of target mRNA transcripts; however, neither isoform has enzymatic properties and thus functions through interactions with other proteins to regulate translational outcomes, but the identity and role of Musashi partner proteins is largely unknown. In this study, we have identified co-associated partner proteins that functionally contribute to Musashi-dependent mRNA translational activation during the maturation of Xenopus oocytes. Using mass spectrometry, we identified 29 co-associated proteins that interact specifically with Musashi1 during oocyte maturation and determined that the Musashi co-associated proteins ePABP, PABP4, LSM14A/B, CELF2, PUM1, ELAV1, ELAV2, and DDX6 attenuated oocyte maturation through individual antisense DNA oligo knockdowns. An assessment of the role of these cofactors in the control of Musashi-dependent target mRNA translation is in progress. In addition to studying co-associated proteins, we have created a computational 3D model of the Musashi1 molecule to assist in our investigation Musashi dimerization. This model has indicated that both Musashi1 dimerization and Musashi1:Musashi2 heterodimerization are energetically favorable, and co-pulldown studies have verified both Musashi1 homo-dimerization and Musashi1:Musashi2 heterodimerization in vivo. Computational modeling of Musashi dimer complexes has also identified the key amino acids necessary for these interactions. The contribution of each co-associated protein’s influence on Musashi-dependent translation, relative to the requirement for Musashi:Musashi dimerization, is expected to provide unparalleled insight into regulation of Musashi action. Moreover, cell type specific regulation of association of Musashi co-factors would directly influence Musashi target mRNA translation in oocyte maturation and during pituitary cell plasticity.

scholarly journals Essential role of translation factor eIF5a in cytokine production and cell cycle regulation in primary CD8 T lymphocytes

2021 ◽  
Author(s):  
Thomas Ching-Jen Tan ◽  
Van Kelly ◽  
Xiaoyan Zou ◽  
Tony Ly ◽  
Rose Zamoyska
Keyword(s):  
Translational Control ◽  
Immune Cell ◽  
Control Point ◽  
Elongation Factor ◽  
Mrna Translation ◽  
Post Translational Modification ◽  
Translation Factors ◽  
Cycle Regulation ◽  
Multiple Immune Cell

Translational control adjusts protein production rapidly and facilitates local cellular responses to environmental conditions. Translation can be regulated through sequestration of mRNAs by regulatory proteins or RNAs, but also by the availability of ribosomes and translation factors which enable initiation and elongation of nascent polypeptides. Traditionally initiation of mRNA translation has been considered to be a major translational control point, however, control of peptide elongation can also play a role. Here we show that post-translational modification of the elongation factor, eIF5a, controls translation of subsets of proteins in naive T-cells upon activation. Sequencing of nascent polypeptides indicated that functional eIF5a was required for the production of proteins which regulate T-cell proliferation and effector function. Control of translation in multiple immune cell lineages is required to co-ordinate immune responses and these data illustrate that translational elongation can contribute to post-transcriptional regulons important for the control of inflammation.

Oocyte determination and the origin of polarity in Drosophila: the role of the spindle genes

Development ◽  
1997 ◽  
Vol 124 (24) ◽  
pp. 4927-4937 ◽  
Author(s):  
A. Gonzalez-Reyes ◽  
H. Elliott ◽  
D. St Johnston
Keyword(s):  
Symmetry Breaking ◽  
Germinal Vesicle ◽  
Follicle Cells ◽  
Axis Formation ◽  
Main Body ◽  
Nurse Cells ◽  
Egg Chambers ◽  
Anterior Posterior ◽  
Oocyte Selection

The two main body axes in Drosophila become polarised as a result of a series of symmetry-breaking steps during oogenesis. Two of the sixteen germline cells in each egg chamber develop as pro-oocytes, and the first asymmetry arises when one of these cells is selected to become the oocyte. Anterior-posterior polarity originates when the oocyte then comes to lie posterior to the nurse cells and signals through the Gurken/Egfr pathway to induce the adjacent follicle cells to adopt a posterior fate. This directs the movement of the germinal vesicle and associated gurken mRNA from the posterior to an anterior corner of the oocyte, where Gurken protein signals for a second time to induce the dorsal follicle cells, thereby polarising the dorsal-ventral axis. Here we describe a group of five genes, the spindle loci, which are required for each of these polarising events. spindle mutants inhibit the induction of both the posterior and dorsal follicle cells by disrupting the localisation and translation of gurken mRNA. Moreover, the oocyte often fails to reach the posterior of mutant egg chambers and differentiates abnormally. Finally, double mutants cause both pro-oocytes to develop as oocytes, by delaying the choice between these two cells. Thus, these mutants reveal a novel link between oocyte selection, oocyte positioning and axis formation in Drosophila, leading us to propose that the spindle genes act in a process that is common to several of these events.

scholarly journals Translational control of a human CDKN1A mRNA splice variant regulates the fate of UVB-irradiated human keratinocytes

2018 ◽  
Vol 29 (1) ◽  
pp. 29-41 ◽  
Author(s):  
Ann E. Collier ◽  
Dan F. Spandau ◽  
Ronald C. Wek
Keyword(s):  
Dna Repair ◽  
Cell Fate ◽  
Translational Control ◽  
Splice Variant ◽  
Mrna Translation ◽  
Human Keratinocytes ◽  
Ultraviolet B ◽  
G1 Arrest ◽  
Adaptive Responses ◽  
Mrna Splice

In response to sublethal ultraviolet B (UVB) irradiation, human keratinocytes transiently block progression of the cell cycle to allow ample time for DNA repair and cell fate determination. These cellular activities are important for avoiding the initiation of carcinogenesis in skin. Central to these processes is the repression of initiation of mRNA translation through GCN2 phosphorylation of eIF2α (eIF2α-P). Concurrent with reduced global protein synthesis, eIF2α-P and the accompanying integrated stress response (ISR) selectively enhance translation of mRNAs involved in stress adaptation. In this study, we elucidated a mechanism for eIF2α-P cytoprotection in response to UVB in human keratinocytes. Loss of eIF2α-P induced by UVB diminished G1 arrest, DNA repair, and cellular senescence coincident with enhanced cell death in human keratinocytes. Genome-wide analysis of translation revealed that the mechanism for these critical adaptive responses by eIF2α-P involved induced expression of CDKN1A encoding the p21 (CIP1/WAF1) protein. We further show that human CDKN1A mRNA splice variant 4 is preferentially translated following stress-induced eIF2α-P by a mechanism mediated in part by upstream ORFs situated in the 5′-leader of CDKN1A mRNA. We conclude that eIF2α-P is cytoprotective in response to UVB by a mechanism featuring translation of a specific splice variant of CDKN1A that facilitates G1 arrest and subsequent DNA repair.

scholarly journals Generally applicable transcriptome-wide analysis of translation using anota2seq

2019 ◽  
Vol 47 (12) ◽  
pp. e70-e70 ◽  
Author(s):  
Christian Oertlin ◽  
Julie Lorent ◽  
Carl Murie ◽  
Luc Furic ◽  
Ivan Topisirovic ◽  
...  
Keyword(s):  
Translational Control ◽  
Gene Expression Regulation ◽  
Neurological Diseases ◽  
Mrna Translation ◽  
Protein Levels ◽  
Pathological Conditions ◽  
Evolutionarily Conserved ◽  
Statistical Identification ◽  
Advance Knowledge

Abstract mRNA translation plays an evolutionarily conserved role in homeostasis and when dysregulated contributes to various disorders including metabolic and neurological diseases and cancer. Notwithstanding that optimal and universally applicable methods are critical for understanding the complex role of translational control under physiological and pathological conditions, approaches to analyze translatomes are largely underdeveloped. To address this, we developed the anota2seq algorithm which outperforms current methods for statistical identification of changes in translation. Notably, in contrast to available analytical methods, anota2seq also allows specific identification of an underappreciated mode of gene expression regulation whereby translation acts as a buffering mechanism which maintains protein levels despite fluctuations in corresponding mRNA abundance (‘translational buffering’). Thus, the universal anota2seq algorithm allows efficient and hitherto unprecedented interrogation of translatomes which is anticipated to advance knowledge regarding the role of translation in homeostasis and disease.

scholarly journals Genome-wide measurement of spatial expression in patterning mutants of Drosophila melanogaster

2016 ◽  
Author(s):  
Peter A. Combs ◽  
Michael B. Eisen
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Cell Fate ◽  
Regulation Of Transcription ◽  
Regulation Of Expression ◽  
Combinatorial Regulation ◽  
Over Expression ◽  
Spatial Positioning ◽  
Pattern Specification

AbstractGenome sequencing has become commonplace, but the understanding of how those genomes ultimately specify cell fate during development is still elusive. Extrapolating insights from deep investigation of a handful of developmentally important Drosophila genes to understanding the regulation of all genes is a major challenge. The developing embryo provides a unique opportunity to study the role of gene expression in pattern specification; the precise and consistent spatial positioning of key transcription factors essentially provides separate transcriptional-readout experiments at a critical point in development.We cryosectioned and sequenced mRNA from single Drosophila melanogaster embryos at the blastoderm stage to screen for spatially-varying regulation of transcription. Expanding on our previous screening of wild type embryos, here we present data from dosage mutants for key maternally provided regulators, including depletion of zelda and hunchback and both over-expression and depletion of bicoid. These data recapitulate all of the expected patterning changes driven by these regulators; for instance, we show spatially-confined up-regulation of expression in the bicoid over-expression condition, and down-regulation of those genes in the bicoid knock-down case, consistent with bicoid’s known function as an anterior-localized activator.Our data highlight the role of combinatorial regulation of patterning gene expression. When comparing changes in multiple conditions, genes responsive to one mutation tend to respond to other mutations in a similar fashion. Furthermore, genes that respond differently to these mutations tend to have more complex patterns of TF binding.

scholarly journals IRES-dependent regulation of FGF-2 mRNA translation in pathophysiological conditions in the mouse

2006 ◽  
Vol 34 (1) ◽  
pp. 17-21 ◽  
Author(s):  
I.G. Gonzalez-Herrera ◽  
L. Prado-Lourenco ◽  
S. Teshima-Kondo ◽  
K. Kondo ◽  
F. Cabon ◽  
...  
Keyword(s):  
Translational Control ◽  
Vascular Complications ◽  
Mrna Translation ◽  
Adult Brain ◽  
Angiogenic Factor ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Nuclear Ribonucleoprotein

The mRNA coding for FGF-2 (fibroblast growth factor 2), a major angiogenic factor, is translated by an IRES (internal ribosome entry site)-dependent mechanism. We have studied the role of the IRES in the regulation of FGF-2 expression in vivo, under pathophysiological conditions, by creating transgenic mice lines expressing bioluminescent bicistronic transgenes. Analysis of FGF-2 IRES activity indicates strong tissue specificity in adult brain and testis, suggesting a role of the IRES in the activation of FGF-2 expression in testis maturation and brain function. We have explored translational control of FGF-2 mRNA under diabetic hyperglycaemic conditions, as FGF-2 is implied in diabetes-related vascular complications. FGF-2 IRES is specifically activated in the aorta wall in streptozotocin-induced diabetic mice, in correlation with increased expression of endogenous FGF-2. Thus, under hyperglycaemic conditions, where cap-dependent translation is blocked, IRES activation participates in FGF-2 overexpression, which is one of the keys of diabetes-linked atherosclerosis aggravation. IRES activation under such pathophysiological conditions may involve ITAFs (IRES trans-acting factors), such as p53 or hnRNP AI (heterogeneous nuclear ribonucleoprotein AI), recently identified as inhibitory or activatory ITAFs respectively for FGF-2 IRES.

scholarly journals Selective mRNA translation during eIF2 phosphorylation induces expression of IBTKα

2014 ◽  
Vol 25 (10) ◽  
pp. 1686-1697 ◽  
Author(s):  
Thomas D. Baird ◽  
Lakshmi Reddy Palam ◽  
Michael E. Fusakio ◽  
Jeffrey A. Willy ◽  
Christopher M. Davis ◽  
...  
Keyword(s):  
Er Stress ◽  
Cell Fate ◽  
Translational Control ◽  
Translational Regulation ◽  
Cultured Cells ◽  
Mrna Translation ◽  
Open Reading Frames ◽  
Α Subunit ◽  
A Genome ◽  
The Unfolded Protein Response

Disruption of protein folding in the endoplasmic reticulum (ER) triggers the unfolded protein response (UPR), a transcriptional and translational control network designed to restore protein homeostasis. Central to the UPR is PKR-like ER kinase (PERK/EIF2AK3) phosphorylation of the α subunit of eIF2 (eIF2α∼P), which represses global translation coincident with preferential translation of mRNAs, such as activating transcription factor 4 (ATF4) and C/EBP-homologous protein (CHOP), that serve to implement UPR transcriptional regulation. In this study, we used sucrose gradient ultracentrifugation and a genome-wide microarray approach to measure changes in mRNA translation during ER stress. Our analysis suggests that translational efficiencies vary over a broad range during ER stress, with the majority of transcripts being either repressed or resistant to eIF2α∼P, whereas a notable cohort of key regulators are subject to preferential translation. From the latter group, we identified the α isoform of inhibitor of Bruton's tyrosine kinase (IBTKα) as being subject to both translational and transcriptional induction during eIF2α∼P in both cell lines and a mouse model of ER stress. Translational regulation of IBTKα mRNA involves stress-induced relief of two inhibitory upstream open reading frames in the 5′-leader of the transcript. Depletion of IBTKα by short hairpin RNA reduced viability of cultured cells coincident with increased caspase 3/7 cleavage, suggesting that IBTKα is a key regulator in determining cell fate during the UPR.

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