Nuclear Actin Filaments and Their Topological Changes in Frog Oocytes

1995 ◽  
Vol 217 (2) ◽  
pp. 385-394 ◽  
Author(s):  
Vladimir N. Parfenov ◽  
Donna S. Davis ◽  
Galina N. Pochukalina ◽  
Clare E. Sample ◽  
Elena A. Bugaeva ◽  
...  
Keyword(s):  
Actin Filaments ◽  
Nuclear Actin ◽  
Topological Changes

To be or not to be assembled: progressing into nuclear actin filaments

2013 ◽  
Vol 14 (11) ◽  
pp. 693-697 ◽  
Author(s):  
Robert Grosse ◽  
Maria K. Vartiainen
Keyword(s):  
Actin Filaments ◽  
Nuclear Actin

scholarly journals Arp2/3 and Unc45 maintain heterochromatin stability in Drosophila polytene chromosomes

2019 ◽  
Author(s):  
George Dialynas ◽  
Laetitia Delabaere ◽  
Irene Chiolo
Keyword(s):  
Actin Filaments ◽  
Genome Stability ◽  
Actin Polymerization ◽  
Cultured Cells ◽  
Nuclear Periphery ◽  
Polytene Chromosomes ◽  
Nuclear Actin ◽  
Nuclear Dynamics ◽  
Ectopic Recombination ◽  
Repair Pathways

AbstractRepairing DNA double-strand breaks (DSBs) is particularly challenging in pericentromeric heterochromatin, where the abundance of repeated sequences exacerbates the risk of ectopic recombination. InDrosophilaKc cells, accurate homologous recombination (HR) repair of heterochromatic DSBs relies on the relocalization of repair sites to the nuclear periphery before Rad51 recruitment and strand invasion. This movement is driven by Arp2/3-dependent nuclear actin filaments and myosins’ ability to walk along them. Conserved mechanisms enable the relocalization of heterochromatic DSBs in mouse cells, and their defects lead to massive ectopic recombination in heterochromatin and chromosome rearrangements. InDrosophilapolytene chromosomes, extensive DNA movement is blocked by a stiff structure of chromosome bundles. Repair pathways in this context are poorly characterized, and whether heterochromatic DSBs relocalize in these cells is unknown. Here, we show that damage in heterochromatin results in relaxation of the heterochromatic chromocenter, consistent with a dynamic response in this structure. Arp2/3, the Arp2/3 activator Scar, and the myosin activator Unc45, are required for heterochromatin stability in polytene cells, suggesting that relocalization enables heterochromatin repair in this tissue. Together, these studies reveal critical roles for actin polymerization and myosin motors in heterochromatin repair and genome stability across different organisms and tissue types.Impact StatementHeterochromatin relies on dedicated pathways for ‘safe’ recombinational repair. In mouse and fly cultured cells, DNA repair requires the movement of repair sites away from the heterochromatin ‘domain’vianuclear actin filaments and myosins. Here, we explore the importance of these pathways inDrosophilasalivary gland cells, which feature a stiff bundle of endoreduplicated polytene chromosomes. Repair pathways in polytene chromosomes are largely obscure and how nuclear dynamics operate in this context is unknown. We show that heterochromatin relaxes in response to damage, and relocalization pathways are necessary for repair and stability of heterochromatic sequences. This deepens our understanding of repair mechanisms in polytenes, revealing unexpected dynamics. It also provides a first understanding of nuclear dynamics responding to replication damage or rDNA breaks, providing a new understanding of the importance of the nucleoskeleton in genome stability. We expect these discoveries to shed light on tumorigenic processes, including therapy-induced cancer relapses.

scholarly journals Nuclear actin filaments recruit cofilin and actin-related protein 3, and their formation is connected with a mitotic block

2014 ◽  
Vol 142 (2) ◽  
pp. 139-152 ◽  
Author(s):  
Alžběta Kalendová ◽  
Ilona Kalasová ◽  
Shota Yamazaki ◽  
Lívia Uličná ◽  
Masahiko Harata ◽  
...  
Keyword(s):  
Actin Filaments ◽  
Nuclear Actin ◽  
Related Protein ◽  
Mitotic Block

scholarly journals DNA Double-Strand Breaks Induce the Nuclear Actin Filaments Formation in Cumulus-Enclosed Oocytes but Not in Denuded Oocytes

PLoS ONE ◽  
2017 ◽  
Vol 12 (1) ◽  
pp. e0170308 ◽  
Author(s):  
Ming-Hong Sun ◽  
Mo Yang ◽  
Feng-Yun Xie ◽  
Wei Wang ◽  
Lili Zhang ◽  
...  
Keyword(s):  
Actin Filaments ◽  
Double Strand Breaks ◽  
Nuclear Actin ◽  
Dna Double Strand Breaks ◽  
Strand Breaks

scholarly journals Correction: Alpha-Herpesvirus Infection Induces the Formation of Nuclear Actin Filaments

2006 ◽  
Vol 2 (9) ◽  
pp. e103 ◽  
Author(s):  
Becket Feierbach ◽  
Silvia Piccinotti ◽  
Margaret Bisher ◽  
Winifred Denk ◽  
Lynn W. Enquist
Keyword(s):  
Actin Filaments ◽  
Nuclear Actin ◽  
Herpesvirus Infection

scholarly journals Actin’ between phase separated domains for heterochromatin repair

2019 ◽  
Author(s):  
Chetan C Rawal ◽  
Christopher P Caridi ◽  
Irene Chiolo
Keyword(s):  
Homologous Recombination ◽  
Actin Filaments ◽  
Repetitive Sequences ◽  
Nuclear Periphery ◽  
Double Strand Breaks ◽  
Nuclear Actin ◽  
Dna Double Strand Breaks ◽  
Directed Motion ◽  
Strand Breaks ◽  
Increased Risk

DNA double-strand breaks (DSBs) are particularly challenging to repair in pericentromeric heterochromatin because of the increased risk of aberrant recombination in highly repetitive sequences. Recent studies have identified specialized mechanisms enabling ‘safe’ homologous recombination (HR) repair in heterochromatin. These include striking nuclear actin filaments (F-actin) and myosins that drive the directed motion of repair sites to the nuclear periphery for ‘safe' repair. Here, we summarize our current understanding of the mechanisms involved, and propose how they might operate in the context of a phase-separated environment.

scholarly journals Actin’ between phase separated domains for heterochromatin repair

2019 ◽  
Author(s):  
Chetan C Rawal ◽  
Christopher P Caridi ◽  
Irene Chiolo
Keyword(s):  
Homologous Recombination ◽  
Actin Filaments ◽  
Repetitive Sequences ◽  
Nuclear Periphery ◽  
Double Strand Breaks ◽  
Nuclear Actin ◽  
Dna Double Strand Breaks ◽  
Directed Motion ◽  
Strand Breaks ◽  
Increased Risk

DNA double-strand breaks (DSBs) are particularly challenging to repair in pericentromeric heterochromatin because of the increased risk of aberrant recombination in highly repetitive sequences. Recent studies have identified specialized mechanisms enabling ‘safe’ homologous recombination (HR) repair in heterochromatin. These include striking nuclear actin filaments (F-actin) and myosins that drive the directed motion of repair sites to the nuclear periphery for ‘safe' repair. Here, we summarize our current understanding of the mechanisms involved, and propose how they might operate in the context of a phase-separated environment.

scholarly journals Dynamizing nuclear actin filaments

2019 ◽  
Vol 56 ◽  
pp. 1-6 ◽  
Author(s):  
Matthias Plessner ◽  
Robert Grosse
Keyword(s):  
Actin Filaments ◽  
Nuclear Actin

scholarly journals DNA damage induces nuclear actin filament assembly by Formin-2 and Spire-1/2 that promotes efficient DNA repair

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Brittany J Belin ◽  
Terri Lee ◽  
R Dyche Mullins
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Actin Filaments ◽  
Protein Misfolding ◽  
Molecular Mechanisms ◽  
Genotoxic Stress ◽  
Nuclear Actin ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Serum Stimulation

Actin filaments assemble inside the nucleus in response to multiple cellular perturbations, including heat shock, protein misfolding, integrin engagement, and serum stimulation. We find that DNA damage also generates nuclear actin filaments—detectable by phalloidin and live-cell actin probes—with three characteristic morphologies: (i) long, nucleoplasmic filaments; (ii) short, nucleolus-associated filaments; and (iii) dense, nucleoplasmic clusters. This DNA damage-induced nuclear actin assembly requires two biologically and physically linked nucleation factors: Formin-2 and Spire-1/Spire-2. Formin-2 accumulates in the nucleus after DNA damage, and depletion of either Formin-2 or actin's nuclear import factor, importin-9, increases the number of DNA double-strand breaks (DSBs), linking nuclear actin filaments to efficient DSB clearance. Nuclear actin filaments are also required for nuclear oxidation induced by acute genotoxic stress. Our results reveal a previously unknown role for nuclear actin filaments in DNA repair and identify the molecular mechanisms creating these nuclear filaments.

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