scholarly journals The RNA binding protein Nab2 regulates the proteome of the developing Drosophila brain

2020 ◽  
Author(s):  
Edwin B. Corgiat ◽  
Sara M. List ◽  
J. Christopher Rounds ◽  
Anita H. Corbett ◽  
Kenneth H. Moberg

AbstractThe human ZC3H14 gene, which encodes a ubiquitously expressed polyadenosine zinc finger RNA binding protein, is mutated in an inherited form of autosomal recessive, non-syndromic intellectual disability. To gain insight into ZC3H14 neurological functions, we previously developed a Drosophila melanogaster model of ZC3H14 loss by deleting the fly ortholog, Nab2. Studies in this invertebrate model reveal that Nab2 controls final patterns of neuron projection within fully developed adult brains. Here, we examine earlier pupal stages and define roles for Nab2 in controlling the dynamic growth of axons into the developing brain mushroom bodies (MBs), which support olfactory learning and memory, and in regulating abundance of a small fraction of the total brain proteome, a portion of which is rescued by overexpression of Nab2 specifically in brain neurons. The group of Nab2-regulated brain proteins, identified by quantitative proteomic analysis, includes the microtubule binding protein Futsch, the neuronal Ig-family transmembrane protein Turtle, the glial:neuron adhesion protein Contactin, the RacGAP Tumbleweed, and the planar cell polarity factor Van Gogh, which collectively link Nab2 to a the processes of brain morphogenesis, neuroblast proliferation, circadian sleep/wake cycles, and synaptic development. Overall, these data indicate that Nab2 controls abundance of a subset of brain proteins during the active process of wiring the pupal brain mushroom body, and thus provide a window into potentially conserved functions of the Nab2/ZC3H14 RNA binding proteins in neurodevelopment and function.

2006 ◽  
Vol 17 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Maria Paola Paronetto ◽  
Francesca Zalfa ◽  
Flavia Botti ◽  
Raffaele Geremia ◽  
Claudia Bagni ◽  
...  

Translational control plays a crucial role during gametogenesis in organisms as different as worms and mammals. Mouse knockout models have highlighted the essential function of many RNA-binding proteins during spermatogenesis. Herein we have investigated the expression and function during mammalian male meiosis of Sam68, an RNA-binding protein implicated in several aspects of RNA metabolism. Sam68 expression and localization within the cells is stage specific: it is expressed in the nucleus of spermatogonia, it disappears at the onset of meiosis (leptotene/zygotene stages), and it accumulates again in the nucleus of pachytene spermatocytes and round spermatids. During the meiotic divisions, Sam68 translocates to the cytoplasm where it is found associated with the polysomes. Translocation correlates with serine/threonine phosphorylation and it is blocked by inhibitors of the mitogen activated protein kinases ERK1/2 and of the maturation promoting factor cyclinB-cdc2 complex. Both kinases associate with Sam68 in pachytene spermatocytes and phosphorylate the regulatory regions upstream and downstream of the Sam68 RNA-binding motif. Molecular cloning of the mRNAs associated with Sam68 in mouse spermatocytes reveals a subset of genes that might be posttranscriptionally regulated by this RNA-binding protein during spermatogenesis. We also demonstrate that Sam68 shuttles between the nucleus and the cytoplasm in secondary spermatocytes, suggesting that it may promote translation of specific RNA targets during the meiotic divisions.


Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 552
Author(s):  
Jasmine Harley ◽  
Benjamin E. Clarke ◽  
Rickie Patani

RNA binding proteins fulfil a wide number of roles in gene expression. Multiple mechanisms of RNA binding protein dysregulation have been implicated in the pathomechanisms of several neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). Oxidative stress and mitochondrial dysfunction also play important roles in these diseases. In this review, we highlight the mechanistic interplay between RNA binding protein dysregulation, oxidative stress and mitochondrial dysfunction in ALS. We also discuss different potential therapeutic strategies targeting these pathways.


2011 ◽  
Vol 22 (16) ◽  
pp. 2875-2885 ◽  
Author(s):  
Mai Nguyen Chi ◽  
Jacques Auriol ◽  
Bernard Jégou ◽  
Dimitris L. Kontoyiannis ◽  
James M.A. Turner ◽  
...  

Posttranscriptional mechanisms are crucial to regulate spermatogenesis. Accurate protein synthesis during germ cell development relies on RNA binding proteins that control the storage, stability, and translation of mRNAs in a tightly and temporally regulated manner. Here, we focused on the RNA binding protein Embryonic Lethal Abnormal Vision (ELAV) L1/Human antigen R (HuR) known to be a key regulator of posttranscriptional regulation in somatic cells but the function of which during gametogenesis has never been investigated. In this study, we have used conditional loss- and gain-of-function approaches to address this issue in mice. We show that targeted deletion of HuR specifically in germ cells leads to male but not female sterility. Mutant males are azoospermic because of the extensive death of spermatocytes at meiotic divisions and failure of spermatid elongation. The latter defect is also observed upon HuR overexpression. To elucidate further the molecular mechanisms underlying spermatogenesis defects in HuR-deleted and -overexpressing testes, we undertook a target gene approach and discovered that heat shock protein (HSP)A2/HSP70-2, a crucial regulator of spermatogenesis, was down-regulated in both situations. HuR specifically binds hspa2 mRNA and controls its expression at the translational level in germ cells. Our study provides the first genetic evidence of HuR involvement during spermatogenesis and reveals Hspa2 as a target for HuR.


2016 ◽  
Vol 44 (5) ◽  
pp. 1321-1337 ◽  
Author(s):  
Andrew R. Clark ◽  
Jonathan L.E. Dean

Twenty years ago, the first description of a tristetraprolin (TTP) knockout mouse highlighted the fundamental role of TTP in the restraint of inflammation. Since then, work from several groups has generated a detailed picture of the expression and function of TTP. It is a sequence-specific RNA-binding protein that orchestrates the deadenylation and degradation of several mRNAs encoding inflammatory mediators. It is very extensively post-translationally modified, with more than 30 phosphorylations that are supported by at least two independent lines of evidence. The phosphorylation of two particular residues, serines 52 and 178 of mouse TTP (serines 60 and 186 of the human orthologue), has profound effects on the expression, function and localisation of TTP. Here, we discuss the control of TTP biology via its phosphorylation and dephosphorylation, with a particular focus on recent advances and on questions that remain unanswered.


Author(s):  
Masashi Yukawa ◽  
Mitsuki Ohishi ◽  
Yusuke Yamada ◽  
Takashi Toda

Cells form a bipolar spindle during mitosis to ensure accurate chromosome segregation. Proper spindle architecture is established by a set of kinesin motors and microtubule-associated proteins. In most eukaryotes, kinesin-5 motors are essential for this process, and genetic or chemical inhibition of their activity leads to the emergence of monopolar spindles and cell death. However, these deficiencies can be rescued by simultaneous inactivation of kinesin-14 motors, as they counteract kinesin-5. We conducted detailed genetic analyses in fission yeast to understand the mechanisms driving spindle assembly in the absence of kinesin-5. Here we show that deletion of the nrp1 gene, which encodes a putative RNA-binding protein with unknown function, can rescue temperature sensitivity caused by cut7-22, a fission yeast kinesin-5 mutant. Interestingly, kinesin-14/Klp2 levels on the spindles in the cut7 mutants were significantly reduced by the nrp1 deletion, although the total levels of Klp2 and the stability of spindle microtubules remained unaffected. Moreover, RNA-binding motifs of Nrp1 are essential for its cytoplasmic localization and function. We have also found that a portion of Nrp1 is spatially and functionally sequestered by chaperone-based protein aggregates upon mild heat stress and limits cell division at high temperatures. We propose that Nrp1 might be involved in post-transcriptional regulation through its RNA-binding ability to promote the loading of Klp2 on the spindle microtubules.


2019 ◽  
Vol 4 (Spring 2019) ◽  
Author(s):  
Alexa Vandenburg

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.


1993 ◽  
Vol 13 (10) ◽  
pp. 6102-6113
Author(s):  
J T Anderson ◽  
M R Paddy ◽  
M S Swanson

Proteins that directly associate with nuclear polyadenylated RNAs, or heterogeneous nuclear RNA-binding proteins (hnRNPs), and those that associate with cytoplasmic mRNAs, or mRNA-binding proteins (mRNPs), play important roles in regulating gene expression at the posttranscriptional level. Previous work with a variety of eukaryotic cells has demonstrated that hnRNPs are localized predominantly within the nucleus whereas mRNPs are cytoplasmic. While studying proteins associated with polyadenylated RNAs in Saccharomyces cerevisiae, we discovered an abundant polyuridylate-binding protein, PUB1, which appears to be both an hnRNP and an mRNP. PUB1 and PAB1, the polyadenylate tail-binding protein, are the two major proteins cross-linked by UV light to polyadenylated RNAs in vivo. The deduced primary structure of PUB1 indicates that it is a member of the ribonucleoprotein consensus sequence family of RNA-binding proteins and is structurally related to the human hnRNP M proteins. Even though the PUB1 protein is a major cellular polyadenylated RNA-binding protein, it is nonessential for cell growth. Indirect cellular immunofluorescence combined with digital image processing allowed a detailed comparison of the intracellular distributions of PUB1 and PAB1. While PAB1 is predominantly, and relatively uniformly, distributed within the cytoplasm, PUB1 is localized in a nonuniform pattern throughout both the nucleus and the cytoplasm. The cytoplasmic distribution of PUB1 is considerably more discontinuous than that of PAB1. Furthermore, sucrose gradient sedimentation analysis demonstrates that PAB1 cofractionates with polyribosomes whereas PUB1 does not. These results suggest that PUB1 is both an hnRNP and an mRNP and that it may be stably bound to a translationally inactive subpopulation of mRNAs within the cytoplasm.


2020 ◽  
Vol 295 (42) ◽  
pp. 14291-14304
Author(s):  
Kathrin Bajak ◽  
Kevin Leiss ◽  
Christine Clayton ◽  
Esteban Erben

In Trypanosoma brucei and related kinetoplastids, gene expression regulation occurs mostly posttranscriptionally. Consequently, RNA-binding proteins play a critical role in the regulation of mRNA and protein abundance. Yet, the roles of many RNA-binding proteins are not understood. Our previous research identified the RNA-binding protein ZC3H5 as possibly involved in gene repression, but its role in controlling gene expression was unknown. We here show that ZC3H5 is an essential cytoplasmic RNA-binding protein. RNAi targeting ZC3H5 causes accumulation of precytokinetic cells followed by rapid cell death. Affinity purification and pairwise yeast two-hybrid analysis suggest that ZC3H5 forms a complex with three other proteins, encoded by genes Tb927.11.4900, Tb927.8.1500, and Tb927.7.3040. RNA immunoprecipitation revealed that ZC3H5 is preferentially associated with poorly translated, low-stability mRNAs, the 5′-untranslated regions and coding regions of which are enriched in the motif (U/A)UAG(U/A). As previously found in high-throughput analyses, artificial tethering of ZC3H5 to a reporter mRNA or other complex components repressed reporter expression. However, depletion of ZC3H5 in vivo caused only very minor decreases in a few targets, marked increases in the abundances of very stable mRNAs, an increase in monosomes at the expense of large polysomes, and appearance of “halfmer” disomes containing two 80S subunits and one 40S subunit. We speculate that the ZC3H5 complex might be implicated in quality control during the translation of suboptimal open reading frames.


2020 ◽  
Vol 21 (13) ◽  
pp. 4571 ◽  
Author(s):  
Cole D. Libner ◽  
Hannah E. Salapa ◽  
Michael C. Levin

Neurodegeneration in multiple sclerosis (MS) is believed to underlie disease progression and permanent disability. Many mechanisms of neurodegeneration in MS have been proposed, such as mitochondrial dysfunction, oxidative stress, neuroinflammation, and RNA-binding protein dysfunction. The purpose of this review is to highlight mechanisms of neurodegeneration in MS and its models, with a focus on RNA-binding protein dysfunction. Studying RNA-binding protein dysfunction addresses a gap in our understanding of the pathogenesis of MS, which will allow for novel therapies to be generated to attenuate neurodegeneration before irreversible central nervous system damage occurs.


2016 ◽  
Vol 113 (19) ◽  
pp. E2579-E2588 ◽  
Author(s):  
Katarzyna P. Adamala ◽  
Daniel A. Martin-Alarcon ◽  
Edward S. Boyden

The ability to monitor and perturb RNAs in living cells would benefit greatly from a modular protein architecture that targets unmodified RNA sequences in a programmable way. We report that the RNA-binding protein PumHD (Pumilio homology domain), which has been widely used in native and modified form for targeting RNA, can be engineered to yield a set of four canonical protein modules, each of which targets one RNA base. These modules (which we call Pumby, for Pumilio-based assembly) can be concatenated in chains of varying composition and length, to bind desired target RNAs. The specificity of such Pumby–RNA interactions was high, with undetectable binding of a Pumby chain to RNA sequences that bear three or more mismatches from the target sequence. We validate that the Pumby architecture can perform RNA-directed protein assembly and enhancement of translation of RNAs. We further demonstrate a new use of such RNA-binding proteins, measurement of RNA translation in living cells. Pumby may prove useful for many applications in the measurement, manipulation, and biotechnological utilization of unmodified RNAs in intact cells and systems.


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