scholarly journals Potential roles of G-quadruplex structures in RNA granules for physiological and pathological phase separation

2021 ◽  
Author(s):  
Sefan Asamitsu ◽  
Norifumi Shioda
Keyword(s):  
Phase Separation ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Separation Process ◽  
Rna Granules ◽  
G Quadruplex ◽  
Phase Separation Process ◽  
Nuclear Rna ◽  
Crowded Environments ◽  
Liquid Liquid Phase Separation

Abstract Cellular liquid–liquid phase separation is a physiologically inevitable phenomenon in molecularly crowded environments inside cells and serves to compartmentalize biomolecules to facilitate several functions, forming cytoplasmic and nuclear RNA granules. Abnormalities in the phase separation process in RNA granules are implicated in the onset of several neurodegenerative diseases; the initial liquid-like phase-separated droplets containing pathogenic proteins are prone to aberrantly mature into solid-like droplets. RNAs are involved in the maturation of physiological and pathological RNA granules and are essential for governing the fate of phase-transition processes. Notably, RNA G-quadruplex (G4RNA), which is the secondary structure of nucleic acids that are formed in guanine-rich sequences, appears to be an advantageous scaffold for RNA-derived phase separation because of its multivalent interactions with RNAs and RNA-binding proteins. Here, we summarize the properties of RNA granules in physiological and pathological phase separation and discuss the potential roles of G4RNA in granules.

scholarly journals SARS-CoV-2 nucleocapsid protein undergoes liquid-liquid phase separation stimulated by RNA and partitions into phases of human ribonucleoproteins

2020 ◽  
Author(s):  
Theodora Myrto Perdikari ◽  
Anastasia C. Murthy ◽  
Veronica H. Ryan ◽  
Scott Watters ◽  
Mandar T. Naik ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Nucleocapsid Protein ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Liquid Phase Separation ◽  
Host Protein ◽  
Host Cells ◽  
Liquid Liquid Phase Separation

AbstractTightly packed complexes of nucleocapsid protein and genomic RNA form the core of viruses and may assemble within viral factories, dynamic compartments formed within the host cells. Here, we examine the possibility that the multivalent RNA-binding nucleocapsid protein (N) from the severe acute respiratory syndrome coronavirus (SARS-CoV-2) compacts RNA via protein-RNA liquid-liquid phase separation (LLPS) and that N interactions with host RNA-binding proteins are mediated by phase separation. To this end, we created a construct expressing recombinant N fused to a N-terminal maltose binding protein tag which helps keep the oligomeric N soluble for purification. Using in vitro phase separation assays, we find that N is assembly-prone and phase separates avidly. Phase separation is modulated by addition of RNA and changes in pH and is disfavored at high concentrations of salt. Furthermore, N enters into in vitro phase separated condensates of full-length human hnRNPs (TDP-43, FUS, and hnRNPA2) and their low complexity domains (LCs). However, N partitioning into the LC of FUS, but not TDP-43 or hnRNPA2, requires cleavage of the solubilizing MBP fusion. Hence, LLPS may be an essential mechanism used for SARS-CoV-2 and other RNA viral genome packing and host protein co-opting, functions necessary for viral replication and hence infectivity.

scholarly journals FUS-dependent liquid-liquid phase separation is an early event in double-strand break repair

2019 ◽  
Author(s):  
Brunno R. Levone ◽  
Silvia C. Lenzken ◽  
Marco Antonaci ◽  
Andreas Maiser ◽  
Alexander Rapp ◽  
...  
Keyword(s):  
Dna Damage ◽  
Phase Separation ◽  
Liquid Phase ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Liquid Phase Separation ◽  
Early Event ◽  
Structured Illumination Microscopy ◽  
Liquid Liquid Phase Separation

AbstractRNA-binding proteins (RBPs) are emerging as important effectors of the cellular DNA damage response (DDR). The RBP FUS is implicated in RNA metabolism and DNA repair, and it undergoes reversible liquid-liquid phase separation (LLPS) in vitro. Here, we demonstrate that FUS-dependent LLPS is necessary for the initiation of the DDR. Using laser microirradiation in FUS-knockout cells, we show that FUS is required for the recruitment to DNA damage sites of the DDR factors KU80, NBS1, 53BP1, and of SFPQ, another RBP implicated in the DDR. The relocation of KU80, NBS1, and SFPQ is similarly impaired by LLPS inhibitors, or LLPS-deficient FUS variants. We also show that LLPS is necessary for efficient γH2AX foci formation. Finally, using super-resolution structured illumination microscopy, we demonstrate that the absence of FUS impairs the proper arrangement of γH2AX nano-foci into higher-order clusters. These findings demonstrate the early requirement for FUS-dependent LLPS in the activation of the DDR and the proper assembly of DSBs repair complexes.

scholarly journals Microtubules as platforms for probing liquid–liquid phase separation in cells – application to RNA-binding proteins

2018 ◽  
Vol 131 (11) ◽  
pp. jcs214692 ◽  
Author(s):  
Alexandre Maucuer ◽  
Bénédicte Desforges ◽  
Vandana Joshi ◽  
Mirela Boca ◽  
Dmitry A. Kretov ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Liquid Phase Separation ◽  
Liquid Liquid Phase Separation ◽  
In Cells

scholarly journals FUS-dependent liquid–liquid phase separation is important for DNA repair initiation

2021 ◽  
Vol 220 (5) ◽  
Author(s):  
Brunno R. Levone ◽  
Silvia C. Lenzken ◽  
Marco Antonaci ◽  
Andreas Maiser ◽  
Alexander Rapp ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Phase Separation ◽  
Liquid Phase ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Liquid Phase Separation ◽  
Structured Illumination Microscopy ◽  
Liquid Liquid Phase Separation

RNA-binding proteins (RBPs) are emerging as important effectors of the cellular DNA damage response (DDR). The RBP FUS is implicated in RNA metabolism and DNA repair, and it undergoes reversible liquid–liquid phase separation (LLPS) in vitro. Here, we demonstrate that FUS-dependent LLPS is necessary for the initiation of the DDR. Using laser microirradiation in FUS-knockout cells, we show that FUS is required for the recruitment to DNA damage sites of the DDR factors KU80, NBS1, and 53BP1 and of SFPQ, another RBP implicated in the DDR. The relocation of KU80, NBS1, and SFPQ is similarly impaired by LLPS inhibitors, or LLPS-deficient FUS variants. We also show that LLPS is necessary for efficient γH2AX foci formation. Finally, using superresolution structured illumination microscopy, we demonstrate that the absence of FUS impairs the proper arrangement of γH2AX nanofoci into higher-order clusters. These findings demonstrate the early requirement for FUS-dependent LLPS in the activation of the DDR and the proper assembly of DSB repair complexes.

scholarly journals Gestörter Kerntransport und Phasentrennung von RNA-Bindeproteinen

BIOspektrum ◽  
2021 ◽  
Vol 27 (4) ◽  
pp. 365-367
Author(s):  
Saskia Hutten ◽  
Dorothee Dormann
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Phase Separation ◽  
Frontotemporal Dementia ◽  
Nuclear Import ◽  
Binding Proteins ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Nuclear Rna ◽  
Lateral Sclerosis

AbstractAmyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are fatal neurodegenerative disordes, whose underlying molecular mechanisms are only beginning to emerge. A common molecular hallmark of both diseases is the relocalization of nuclear RNA-binding proteins (RBP) into cytoplasmic aggregates. Defects in nuclear import and aberrant phase separation appear to underlie RBP mislocalization and aggregation and could potentially be targeted in future therapies.

scholarly journals G-quadruplex DNA inhibits unwinding activity but promotes liquid–liquid phase separation by the DEAD-box helicase Ded1p

2021 ◽  
Author(s):  
Jun Gao ◽  
Zhaofeng Gao ◽  
Andrea A. Putnam ◽  
Alicia K. Byrd ◽  
Sarah L. Venus ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Intrinsically Disordered ◽  
Dead Box ◽  
G4 Dna ◽  
G Quadruplex ◽  
The Dead ◽  
Liquid Liquid Phase Separation

G-quadruplex (G4) DNA inhibits RNA unwinding activity but promotes liquid–liquid phase separation of the DEAD-box helicase Ded1p in vitro and in cells. This highlights multifaceted effects of G4DNA on an enzyme with intrinsically disordered domains.

Sign in / Sign up

Export Citation Format

Share Document