scholarly journals An eIF4E-binding protein regulates katanin protein levels in C. elegans embryos

2009 ◽  
Vol 187 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Wei Li ◽  
Leah R. DeBella ◽  
Tugba Guven-Ozkan ◽  
Rueyling Lin ◽  
Lesilee S. Rose
Keyword(s):  
Untranslated Region ◽  
Rna Binding ◽  
Binding Protein ◽  
Degradation Pathway ◽  
Translational Repression ◽  
Spindle Orientation ◽  
P Granules ◽  
C Elegans ◽  
Microtubule Severing ◽  
Protein Levels

In Caenorhabditis elegans, the MEI-1–katanin microtubule-severing complex is required for meiosis, but must be down-regulated during the transition to embryogenesis to prevent defects in mitosis. A cullin-dependent degradation pathway for MEI-1 protein has been well documented. In this paper, we report that translational repression may also play a role in MEI-1 down-regulation. Reduction of spn-2 function results in spindle orientation defects due to ectopic MEI-1 expression during embryonic mitosis. MEL-26, which is both required for MEI-1 degradation and is itself a target of the cullin degradation pathway, is present at normal levels in spn-2 mutant embryos, suggesting that the degradation pathway is functional. Cloning of spn-2 reveals that it encodes an eIF4E-binding protein that localizes to the cytoplasm and to ribonucleoprotein particles called P granules. SPN-2 binds to the RNA-binding protein OMA-1, which in turn binds to the mei-1 3′ untranslated region. Thus, our results suggest that SPN-2 functions as an eIF4E-binding protein to negatively regulate translation of mei-1.

scholarly journals mRNA localization is linked to translation regulation in the Caenorhabditis elegans germ lineage

2020 ◽  
Author(s):  
Dylan M. Parker ◽  
Lindsay P. Winkenbach ◽  
Samuel P. Boyson ◽  
Matthew N. Saxton ◽  
Camryn Daidone ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Regulatory Control ◽  
Translational Repression ◽  
Translation Regulation ◽  
Germline Development ◽  
P Granules ◽  
C Elegans ◽  
Early Embryos

AbstractCaenorhabditis elegans early embryos generate cell-specific transcriptomes despite lacking active transcription. This presents an opportunity to study mechanisms of post-transcriptional regulatory control. In seeking the mechanisms behind this patterning, we discovered that some cell-specific mRNAs accumulate non-homogenously within cells, localizing to membranes, P granules (associated with progenitor germ cells in the P lineage), and P-bodies (associated with RNA processing). Transcripts differed in their dependence on 3’UTRs and RNA Binding Proteins, suggesting diverse regulatory mechanisms. Notably, we found strong but imperfect correlations between low translational status and P granule localization within the progenitor germ lineage. By uncoupling these, we untangled a long-standing question: Are mRNAs directed to P granules for translational repression or do they accumulate there as a downstream step? We found translational repression preceded P granule localization and could occur independent of it. Further, disruption of translation was sufficient to send homogenously distributed mRNAs to P granules. Overall, we show transcripts important for germline development are directed to P granules by translational repression, and this, in turn, directs their accumulation in the progenitor germ lineage where their repression can ultimately be relieved.SummaryMaternally loaded mRNAs localize non-homogeneously within C. elegans early embryos correlating with their translational status and lineage-specific fates.

FOG-2, a novel F-box containing protein, associates with the GLD-1 RNA binding protein and directs male sex determination in the C. elegans hermaphrodite germline

Development ◽  
2000 ◽  
Vol 127 (24) ◽  
pp. 5265-5276 ◽  
Author(s):  
R. Clifford ◽  
M.H. Lee ◽  
S. Nayak ◽  
M. Ohmachi ◽  
F. Giorgini ◽  
...  
Keyword(s):  
Sex Determination ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Translational Repression ◽  
Specific Substrate ◽  
Interaction Domain ◽  
C Elegans ◽  
Male Sex ◽  
F Box Protein

Male sex determination in the Caenorhabditis elegans hermaphrodite germline requires translational repression of tra-2 mRNA by the GLD-1 RNA binding protein. We cloned fog-2 by finding that its gene product physically interacts with GLD-1, forming a FOG-2/GLD-1/tra-2 3′untranslated region ternary complex. FOG-2 has an N-terminal F-box and a novel C-terminal domain called FTH. Canonical F-box proteins act as bridging components of the SCF ubiquitin ligase complex; the N-terminal F-box binds a Skp1 homolog, recruiting ubiquination machinery, while a C-terminal protein-protein interaction domain binds a specific substrate for degradation. However, since both fog-2 and gld-1 are necessary for spermatogenesis, FOG-2 cannot target GLD-1 for ubiquitin-mediated degradation. We propose that FOG-2 also acts as a bridge, bringing GLD-1 bound to tra-2 mRNA into a multiprotein translational repression complex, thus representing a novel function for an F-box protein. fog-2 is a member of a large, apparently rapidly evolving, C. elegans gene family that has expanded, in part, by local duplications; fog-2 related genes have not been found outside nematodes. fog-2 may have arisen during evolution of self-fertile hermaphroditism from an ancestral female/male species.

scholarly journals A testis cytoplasmic RNA-binding protein that has the properties of a translational repressor.

1996 ◽  
Vol 16 (6) ◽  
pp. 3023-3034 ◽  
Author(s):  
K Lee ◽  
M A Fajardo ◽  
R E Braun
Keyword(s):  
Germ Cell ◽  
Untranslated Region ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Male Germ Cell ◽  
Translational Repression ◽  
Translational Repressor ◽  
Germ Cell Differentiation

Translation of the mouse protamine 1 (Prm-1) mRNA is repressed for several days during male germ cell differentiation. With the hope of cloning genes that regulate the translational repression of Prm-1, we screened male germ cell cDNA expression libraries with the 3' untranslated region of the Prm-1 RNA. From this screen we obtained two independent clones that encode Prbp, a Prm-1 RNA-binding protein. Prbp contains two copies of a double-stranded-RNA-binding domain. In vitro, the protein binds to a portion of the Prm-1 3' untranslated region previously shown to be sufficient for translational repression in transgenic mice, as well as to poly(I). poly(C). Prbp protein is present in multiple forms in cytoplasmic extracts prepared from wild-type mouse testes and is absent from testes of germ cell-deficient mouse mutants, suggesting that Prbp is restricted to the germ cells of the testis. Immunocytochemical localization confirmed that Prbp is present in the cytoplasmic compartment of late-stage meiotic cells and haploid round spermatids. Recombinant Prbp protein inhibits the translation of multiple mRNAs in a wheat germ lysate, suggesting that Prbp acts to repress translation in round spermatids. While this protein lacks complete specificity for Prm-1-containing RNAs in vitro, the properties of Prbp are consistent with it acting as a general repressor of translation.

scholarly journals Identification and characterization of a 44 kDa protein that binds specifically to the 3′-untranslated region of CYP2a5 mRNA: inducibility, subcellular distribution and possible role in mRNA stabilization

1996 ◽  
Vol 313 (3) ◽  
pp. 1029-1037 ◽  
Author(s):  
Olivier GENESTE ◽  
Françoise RAFFALLI ◽  
Matti A. LANG
Keyword(s):  
Half Life ◽  
Untranslated Region ◽  
Translational Regulation ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Blocking Agent ◽  
Subcellular Fractionation ◽  
Mrna Stabilization ◽  
Nuclear Extracts

Stabilization of mRNA is important in the regulation of CYP2a5 expression but the factors involved in the process are not known [Aida and Negishi (1991) Biochemistry 30, 8041–8045]. In this paper, we describe, for the first time, a protein that binds specifically to the 3′-untranslated region of CYP2a5 mRNA and which is inducible by pyrazole, a compound known to increase the half-life of CYP2a5 mRNA. We also demonstrate that pyrazole treatment causes an elongation of the CYP2a5 mRNA poly(A) tail, and that phenobarbital, which is transcriptional activator of the CYP2a5 gene that does not affect the mRNA half-life, neither induces the RNA-binding protein nor affects the poly(A) tail size. SDS/PAGE of the UV-cross-linked RNA–protein complex demonstrated that the RNA-binding protein has an apparent molecular mass of 44 kDa. The protein-binding site was localized to a 70-nucleotide region between bases 1585 and 1655. Treatment of cytoplasmic extracts with an SH-oxidizing agent, diamide, an SH-blocking agent, N-ethylmaleimide or potato acid phosphatase abolished complex-formation, suggesting that the CYP2a5 mRNA-binding protein is subject to post-translational regulation. Subcellular fractionation showed that the 44 kDa protein is present in polyribosomes and nuclei, and that its apparent induction is much stronger in polyribosomes than in nuclear extracts. We propose that this 44 kDA RNA-binding protein is involved in the stabilization of CYP2a5 mRNA by controlling the length of the poly(A) tail.

scholarly journals Eukaryotic initiation factor EIF-3.G augments mRNA translation efficiency to regulate neuronal activity

2021 ◽  
Author(s):  
Stephen M Blazie ◽  
Seika Takayanagi-Kiya ◽  
Katherine A McCulloch ◽  
Yishi Jin
Keyword(s):  
Rna Binding ◽  
Mrna Translation ◽  
Initiation Factor ◽  
Translation Efficiency ◽  
Dependent Manner ◽  
Control Activity ◽  
C Elegans ◽  
Protein Levels ◽  
Neuronal Protein

AbstractThe translation initiation complex eIF3 imparts specialized functions to regulate protein expression. However, understanding of eIF3 activities in neurons remains limited despite widespread dysregulation of eIF3 subunits in neurological disorders. Here, we report a selective role of theC. elegansRNA-binding subunit EIF-3.G in shaping the neuronal protein landscape. We identify a missense mutation in the conserved Zinc-Finger (ZF) of EIF-3.G that acts in a gain-of-function manner to dampen neuronal hyperexcitation. Using neuron type-specific seCLIP, we systematically mapped EIF-3.G-mRNA interactions and identified EIF-3.G occupancy on GC-rich 5′UTRs of a select set of mRNAs enriched in activity-dependent functions. We demonstrate that the ZF mutation in EIF-3.G alters translation in a 5′UTR dependent manner. Our study reveals anin vivomechanism for eIF3 in governing neuronal protein levels to control activity states and offers insights into how eIF3 dysregulation contributes to neuronal disorders.

scholarly journals Investigating the Roles of RNA Binding Protein Combinations in Neuronal Function and Organismal Behavior

2019 ◽  
Vol 4 (Spring 2019) ◽  
Author(s):  
Alexa Vandenburg
Keyword(s):  
Binding Sites ◽  
Neuronal Development ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Wild Type ◽  
C Elegans ◽  
Neuronal Gene ◽  
Touch Response

The Norris lab recently identified two RNA binding proteins required for proper neuron-specific splicing. The lab conducted touch- response behavioral assays to assess the function of these proteins in touch-sensing neurons. After isolating C. elegans worms with specific phenotypes, the lab used automated computer tracking and video analysis to record the worms’ behavior. The behavior of mutant worms differed from that of wild-type worms. The Norris lab also discovered two possible RNA binding protein sites in SAD-1, a neuronal gene implicated in the neuronal development of C. elegans1. These two binding sites may control the splicing of SAD-1. The lab transferred mutated DNA into the genome of wild-type worms by injecting a mutated plasmid. The newly transformed worms fluoresced green, indicating that the two binding sites control SAD-1 splicing.

Analysis of RNA associated with P granules in germ cells of C. elegans adults

Development ◽  
2001 ◽  
Vol 128 (8) ◽  
pp. 1287-1298 ◽  
Author(s):  
J.A. Schisa ◽  
J.N. Pitt ◽  
J.R. Priess
Keyword(s):  
Germ Cells ◽  
Rna Binding ◽  
Nuclear Surface ◽  
Binding Motifs ◽  
P Granules ◽  
C Elegans ◽  
Specific Mrnas ◽  
Tubulin Mrna ◽  
Protein Components ◽  
Cytoplasmic Structures

P granules are cytoplasmic structures of unknown function that are associated with germ nuclei in the C. elegans gonad, and are localized exclusively to germ cells, or germ cell precursors, throughout the life cycle. All the known protein components of P granules contain putative RNA-binding motifs, suggesting that RNA is involved in either the structure or function of the granules. However, no specific mRNAs have been identified within P granules in the gonad. We show here that P granules normally contain a low level of RNA, and describe conditions that increase this level. We present evidence that several, diverse mRNAs, including pos-1, mex-1, par-3, skn-1, nos-2 and gld-1 mRNA, are present at least transiently within P granules. In contrast, actin and tubulin mRNA and rRNA are either not present in P granules, or are present at relatively low levels. We show that pgl-1 and the glh (Vasa-related) gene family, which encode protein components of P granules, do not appear essential for RNA to concentrate in P granules; these proteins may instead function in events that are a prerequisite for RNAs to be transported efficiently from the nuclear surface.

CHMP2B regulates TDP-43 phosphorylation and cytotoxicity independent of autophagy via CK1

2021 ◽  
Vol 221 (1) ◽  
Author(s):  
Xue Deng ◽  
Xing Sun ◽  
Wenkai Yue ◽  
Yongjia Duan ◽  
Rirong Hu ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Down Regulation ◽  
Protein Levels ◽  
Modifying Effect

The ESCRT protein CHMP2B and the RNA-binding protein TDP-43 are both associated with ALS and FTD. The pathogenicity of CHMP2B has mainly been considered a consequence of autophagy–endolysosomal dysfunction, whereas protein inclusions containing phosphorylated TDP-43 are a pathological hallmark of ALS and FTD. Intriguingly, TDP-43 pathology has not been associated with the FTD-causing CHMP2BIntron5 mutation. In this study, we identify CHMP2B as a modifier of TDP-43–mediated neurodegeneration in a Drosophila screen. Down-regulation of CHMP2B reduces TDP-43 phosphorylation and toxicity in flies and mammalian cells. Surprisingly, although CHMP2BIntron5 causes dramatic autophagy dysfunction, disturbance of autophagy does not alter TDP-43 phosphorylation levels. Instead, we find that inhibition of CK1, but not TTBK1/2 (all of which are kinases phosphorylating TDP-43), abolishes the modifying effect of CHMP2B on TDP-43 phosphorylation. Finally, we uncover that CHMP2B modulates CK1 protein levels by negatively regulating ubiquitination and the proteasome-mediated turnover of CK1. Together, our findings propose an autophagy-independent role and mechanism of CHMP2B in regulating CK1 abundance and TDP-43 phosphorylation.

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