scholarly journals Germline RNA helicases couple RNA binding to P granule assembly at nuclear periphery

2019 ◽  
Author(s):  
Wenjun Chen ◽  
Yabing Hu ◽  
Charles Lang ◽  
Jordan S Brown ◽  
Xiaoyan Song ◽  
...  

ABSTRACTP granules are phase-separated liquid droplets that play important roles in the maintenance of the germ cell fate in C. elegans. The localization and formation of P granules are highly dynamic, but mechanisms that regulate such processes remain poorly understood. Here we show that germline RNA helicases (GLHs) control the formation and disassembly of germ granules through their binding and release of RNAs, respectively. In addition, the FGG repeats in the GLHs promote the formation of germ granules at the perinucleus. Proteomic analyses of a mutation that traps RNA-bound GLH-1 complex revealed transient interactions of GLH-1 with several Argonautes and RNA binding proteins. Finally, we found that defects in perinuclear P granule formation correlate with the fertility defects observed in various GLH mutants. Together, our results highlight the versatile roles of RNA helicases in controlling the formation of liquid droplets in space and time.

Genetics ◽  
2020 ◽  
Vol 215 (2) ◽  
pp. 421-434 ◽  
Author(s):  
Wenjun Chen ◽  
Yabing Hu ◽  
Charles F. Lang ◽  
Jordan S. Brown ◽  
Sierra Schwabach ◽  
...  

P granules are phase-separated liquid droplets that play important roles in the maintenance of germ cell fate in Caenorhabditis elegans. Both the localization and formation of P granules are highly dynamic, but mechanisms that regulate such processes remain poorly understood. Here, we show evidence that the VASA-like germline RNA helicase GLH-1 couples distinct steps of its ATPase hydrolysis cycle to control the formation and disassembly of P granules. In addition, we found that the phenylalanine-glycine-glycine repeats in GLH-1 promote its localization at the perinucleus. Proteomic analyses of the GLH-1 complex with a GLH-1 mutation that interferes with P granule disassembly revealed transient interactions of GLH-1 with several Argonautes and RNA-binding proteins. Finally, we found that defects in recruiting the P granule component PRG-1 to perinuclear foci in the adult germline correlate with the fertility defects observed in various GLH-1 mutants. Together, our results highlight the versatile roles of an RNA helicase in controlling the formation of liquid droplets in space and time.


2011 ◽  
Vol 192 (6) ◽  
pp. 929-937 ◽  
Author(s):  
Momoyo Hanazawa ◽  
Masafumi Yonetani ◽  
Asako Sugimoto

Germ granules are germ lineage–specific ribonucleoprotein (RNP) complexes, but how they are assembled and specifically segregated to germ lineage cells remains unclear. Here, we show that the PGL proteins PGL-1 and PGL-3 serve as the scaffold for germ granule formation in Caenorhabditis elegans. Using cultured mammalian cells, we found that PGL proteins have the ability to self-associate and recruit RNPs. Depletion of PGL proteins from early C. elegans embryos caused dispersal of other germ granule components in the cytoplasm, suggesting that PGL proteins are essential for the architecture of germ granules. Using a structure–function analysis in vivo, we found that two functional domains of PGL proteins contribute to germ granule assembly: an RGG box for recruiting RNA and RNA-binding proteins and a self-association domain for formation of globular granules. We propose that self-association of scaffold proteins that can bind to RNPs is a general mechanism by which large RNP granules are formed.


2020 ◽  
Author(s):  
Melissa J. MacPherson ◽  
Sarah L Erickson ◽  
Drayden Kopp ◽  
Pengqiang Wen ◽  
Mohammadreza Aghanoori ◽  
...  

Abstract The formation of the cerebral cortex requires balanced expansion and differentiation of neural progenitor cells, the fate choice of which requires regulation at many steps of gene expression. As progenitor cells often exhibit transcriptomic stochasticity, the ultimate output of cell fate-determining genes must be carefully controlled at the post-transcriptional level, but how this is orchestrated is poorly understood. Here we report that de novo missense variants in an RNA-binding protein CELF2 cause human cortical malformations and perturb neural progenitor cell fate decisions in mice by disrupting the nucleocytoplasmic transport of CELF2. In self-renewing neural progenitors, CELF2 is localized in the cytoplasm where it binds and coordinates mRNAs that encode cell fate regulators and neurodevelopmental disorder-related factors. The translocation of CELF2 into the nucleus releases mRNAs for translation and thereby triggers neural progenitor differentiation. Our results reveal a mechanism by which transport of CELF2 between discrete subcellular compartments orchestrates an RNA regulon to instruct cell fates in cerebral cortical development.


2015 ◽  
Vol 60 (2) ◽  
pp. 208-219 ◽  
Author(s):  
Yuan Lin ◽  
David S.W. Protter ◽  
Michael K. Rosen ◽  
Roy Parker

2019 ◽  
Vol 97 (1) ◽  
pp. 10-20 ◽  
Author(s):  
Laura P.M.H. de Rooij ◽  
Derek C.H. Chan ◽  
Ava Keyvani Chahi ◽  
Kristin J. Hope

Normal hematopoiesis is sustained through a carefully orchestrated balance between hematopoietic stem cell (HSC) self-renewal and differentiation. The functional importance of this axis is underscored by the severity of disease phenotypes initiated by abnormal HSC function, including myelodysplastic syndromes and hematopoietic malignancies. Major advances in the understanding of transcriptional regulation of primitive hematopoietic cells have been achieved; however, the post-transcriptional regulatory layer that may impinge on their behavior remains underexplored by comparison. Key players at this level include RNA-binding proteins (RBPs), which execute precise and highly coordinated control of gene expression through modulation of RNA properties that include its splicing, polyadenylation, localization, degradation, or translation. With the recent identification of RBPs having essential roles in regulating proliferation and cell fate decisions in other systems, there has been an increasing appreciation of the importance of post-transcriptional control at the stem cell level. Here we discuss our current understanding of RBP-driven post-transcriptional regulation in HSCs, its implications for normal, perturbed, and malignant hematopoiesis, and the most recent technological innovations aimed at RBP–RNA network characterization at the systems level. Emerging evidence highlights RBP-driven control as an underappreciated feature of primitive hematopoiesis, the greater understanding of which has important clinical implications.


2015 ◽  
Author(s):  
◽  
Erin C. Boone

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Meiotic silencing by unpaired DNA (MSUD) is an RNA interference (RNAi) pathway in Neurospora crassa that detects genes without a homologous partner and silences them for the duration of sexual development. In this study, we have further elucidated the function of known MSUD proteins, identified novel proteins that are required for MSUD, and demonstrated the conservation of RNAi-related processes at the nuclear periphery. We began by showing SAD-2 is crucial for the localization of other MSUD proteins in the perinuclear region. These data suggest that SAD-2 works as a scaffold protein and that proper function of MSUD, like other germline RNAi-like systems, is reliant on the presence of silencing proteins in the perinuclear region. An MSUD suppression assay identified two novel MSUD proteins, SAD-Y and SAD-B'. Even though SAD-Y and its homologs contain a conserved putative RNA- binding motif, they have yet to be assigned to a biochemical pathway. Our work here has linked silencing to SAD-Y-like proteins. SAD-Y has been shown to interact with other MSUD factors in both the nucleus and at the nuclear periphery. SAD-B's homolog has been found in the nuage, an epicenter for RNA-binding proteins involved in post-transcriptional regulation for Drosophila germline cells. SAD-B interacts with core MSUD proteins and has an especially intimate association with SMS-2, which requires it for localization. Furthermore, bimolecular fluorescence complementation (BiFC) revealed that SAD-B' interacts with a Golgi retrograde transport protein and an autophagy marker protein, suggesting the importance of the endomembrane system in this RNAi process.


2020 ◽  
Vol 11 (7) ◽  
Author(s):  
Jessica Rea ◽  
Valentina Menci ◽  
Paolo Tollis ◽  
Tiziana Santini ◽  
Alexandros Armaos ◽  
...  

Abstract Neuronal differentiation is a timely and spatially regulated process, relying on precisely orchestrated gene expression control. The sequential activation/repression of genes driving cell fate specification is achieved by complex regulatory networks, where transcription factors and noncoding RNAs work in a coordinated manner. Herein, we identify the long noncoding RNA HOTAIRM1 (HOXA Transcript Antisense RNA, Myeloid-Specific 1) as a new player in neuronal differentiation. We demonstrate that the neuronal-enriched HOTAIRM1 isoform epigenetically controls the expression of the proneural transcription factor NEUROGENIN 2 that is key to neuronal fate commitment and critical for brain development. We also show that HOTAIRM1 activity impacts on NEUROGENIN 2 downstream regulatory cascade, thus contributing to the achievement of proper neuronal differentiation timing. Finally, we identify the RNA-binding proteins HNRNPK and FUS as regulators of HOTAIRM1 biogenesis and metabolism. Our findings uncover a new regulatory layer underlying NEUROGENIN 2 transitory expression in neuronal differentiation and reveal a previously unidentified function for the neuronal-induced long noncoding RNA HOTAIRM1.


Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1958
Author(s):  
Ella Alkalay ◽  
Chen Gam Ze Letova Refael ◽  
Irit Shoval ◽  
Noa Kinor ◽  
Ronit Sarid ◽  
...  

RNA-binding proteins, particularly splicing factors, localize to sub-nuclear domains termed nuclear speckles. During certain viral infections, as the nucleus fills up with replicating virus compartments, host cell chromatin distribution changes, ending up condensed at the nuclear periphery. In this study we wished to determine the fate of nucleoplasmic RNA-binding proteins and nuclear speckles during the lytic cycle of the Kaposi’s sarcoma associated herpesvirus (KSHV). We found that nuclear speckles became fewer and dramatically larger, localizing at the nuclear periphery, adjacent to the marginalized chromatin. Enlarged nuclear speckles contained splicing factors, whereas other proteins were nucleoplasmically dispersed. Polyadenylated RNA, typically found in nuclear speckles under regular conditions, was also found in foci separated from nuclear speckles in infected cells. Poly(A) foci did not contain lncRNAs known to colocalize with nuclear speckles but contained the poly(A)-binding protein PABPN1. Examination of the localization of spliced viral RNAs revealed that some spliced transcripts could be detected within the nuclear speckles. Since splicing is required for the maturation of certain KSHV transcripts, we suggest that the infected cell does not dismantle nuclear speckles but rearranges their components at the nuclear periphery to possibly serve in splicing and transport of viral RNAs into the cytoplasm.


Reproduction ◽  
2016 ◽  
Vol 151 (4) ◽  
pp. 351-367 ◽  
Author(s):  
Zhuxia Zheng ◽  
Hongmei Li ◽  
Qinfen Zhang ◽  
Lele Yang ◽  
Huayu Qi

Cell lineage determination during early embryogenesis has profound effects on adult animal development. Pre-patterning of embryos, such as that of Drosophila and Caenorhabditis elegans, is driven by asymmetrically localized maternal or zygotic factors, including mRNA species and RNA binding proteins. However, it is not clear how mammalian early embryogenesis is regulated and what the early cell fate determinants are. Here we show that, in mouse, mitochondrial ribosomal RNAs (mtrRNAs) are differentially distributed between 2-cell sister blastomeres. This distribution pattern is not related to the overall quantity or activity of mitochondria which appears equal between 2-cell sister blastomeres. Like in lower species, 16S mtrRNA is found to localize in the cytoplasm outside of mitochondria in mouse 2-cell embryos. Alterations of 16S mtrRNA levels in one of the 2-cell sister blastomere via microinjection of either sense or anti-sense RNAs drive its progeny into different cell lineages in blastocyst. These results indicate that mtrRNAs are differentially distributed among embryonic cells at the beginning of embryogenesis in mouse and they are functionally involved in the regulation of cell lineage allocations in blastocyst, suggesting an underlying molecular mechanism that regulates pre-implantation embryogenesis in mouse.


Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 167 ◽  
Author(s):  
Ohashi ◽  
Shiina

Spatiotemporal translational regulation plays a key role in determining cell fate and function. Specifically, in neurons, local translation in dendrites is essential for synaptic plasticity and long-term memory formation. To achieve local translation, RNA-binding proteins in RNA granules regulate target mRNA stability, localization, and translation. To date, mRNAs localized to dendrites have been identified by comprehensive analyses. In addition, mRNAs associated with and regulated by RNA-binding proteins have been identified using various methods in many studies. However, the results obtained from these numerous studies have not been compiled together. In this review, we have catalogued mRNAs that are localized to dendrites and are associated with and regulated by the RNA-binding proteins fragile X mental retardation protein (FMRP), RNA granule protein 105 (RNG105, also known as Caprin1), Ras-GAP SH3 domain binding protein (G3BP), cytoplasmic polyadenylation element binding protein 1 (CPEB1), and staufen double-stranded RNA binding proteins 1 and 2 (Stau1 and Stau2) in RNA granules. This review provides comprehensive information on dendritic mRNAs, the neuronal functions of mRNA-encoded proteins, the association of dendritic mRNAs with RNA-binding proteins in RNA granules, and the effects of RNA-binding proteins on mRNA regulation. These findings provide insights into the mechanistic basis of protein-synthesis-dependent synaptic plasticity and memory formation and contribute to future efforts to understand the physiological implications of local regulation of dendritic mRNAs in neurons.


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