scholarly journals Absence of the Spindle Assembly Checkpoint restores mitotic fidelity upon loss of sister chromatid cohesion

2018 ◽  
Author(s):  
Rui D. Silva ◽  
Mihailo Mirkovic ◽  
Leonardo G. Guilgur ◽  
Om S. Rathore ◽  
Rui Gonçalo Martinho ◽  
...  
Keyword(s):  
Cell Survival ◽  
Sister Chromatid ◽  
Spindle Assembly Checkpoint ◽  
Genome Shuffling ◽  
Spindle Assembly ◽  
Sister Chromatid Cohesion ◽  
Abnormal Development ◽  
Wing Development ◽  
Cohesin Complex ◽  
Chromatid Cohesion

AbstractSister chromatid cohesion is essential for faithful mitosis, as premature cohesion loss leads to random chromosome segregation and aneuploidy, resulting in abnormal development. To identify specific conditions capable of restoring defects associated with cohesion loss, we screened for genes whose depletion modulates Drosophila wing development when sister chromatid cohesion is impaired. Cohesion deficiency was induced by knock-down of the acetyltransferase Separation anxiety (San)/Naa50, a cohesin complex stabilizer. Several genes whose function impacts wing development upon cohesion loss were identified. Surprisingly, knockdown of key Spindle Assembly Checkpoint (SAC) proteins, Mad2 and Mps1, suppressed developmental defects associated with San depletion. SAC impairment upon cohesin removal, triggered by San depletion or artificial removal of the cohesin complex, prevented extensive genome shuffling, reduced segregation defects and restored cell survival. This counterintuitive phenotypic suppression was caused by an intrinsic bias for efficient chromosome bi-orientation at mitotic entry, coupled with slow engagement of error-correction reactions. We conclude that mitotic timing determines the severity of defects associated with cohesion deficiency. Therefore, although divisions are still error-prone, SAC inactivation enhances cell survival and tissue homeostasis upon cohesion loss.

scholarly journals Absence of the Spindle Assembly Checkpoint Restores Mitotic Fidelity upon Loss of Sister Chromatid Cohesion

2018 ◽  
Vol 28 (17) ◽  
pp. 2837-2844.e3 ◽  
Author(s):  
Rui D. Silva ◽  
Mihailo Mirkovic ◽  
Leonardo G. Guilgur ◽  
Om S. Rathore ◽  
Rui Gonçalo Martinho ◽  
...  
Keyword(s):  
Sister Chromatid ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Sister Chromatid Cohesion ◽  
Chromatid Cohesion

scholarly journals Securin and Separase Phosphorylation Act Redundantly to Maintain Sister Chromatid Cohesion in Mammalian Cells

2005 ◽  
Vol 16 (10) ◽  
pp. 4725-4732 ◽  
Author(s):  
Xingxu Huang ◽  
Rashieda Hatcher ◽  
J. Philippe York ◽  
Pumin Zhang
Keyword(s):  
Sister Chromatid ◽  
Mammalian Cells ◽  
Genome Stability ◽  
Spindle Assembly Checkpoint ◽  
Budding Yeast ◽  
Embryonic Stem ◽  
Spindle Assembly ◽  
Sister Chromatid Cohesion ◽  
Chromatid Cohesion ◽  
Spindle Microtubules

The spindle assembly checkpoint monitors the integrity of the spindle microtubules, which attach to sister chromatids at kinetochores and play a vital role in preserving genome stability by preventing missegregation. A key target of the spindle assembly checkpoint is securin, the separase inhibitor. In budding yeast, loss of securin results in precocious sister chromatid separation when the microtubule spindle is disrupted. However, in contrast to budding yeast, mammalian securin is not required for spindle checkpoint, suggesting that there are redundant mechanisms controlling the dissolution of sister chromatid cohesion in the absence of securin. One candidate mechanism is the inhibitory phosphorylation of separase. We generated a nonphosphorylable point mutant (S1121A) separase allele in securin-/- mouse embryonic stem cells. Securin-/-separase+/S1121A cells are viable but fail to maintain sister chromatid cohesion in response to the disruption of spindle microtubules, show enhanced sensitivity to nocodazole, and cannot recover from prometaphase arrest.

scholarly journals Scc2/Nipbl hops between chromosomal cohesin rings after loading

2017 ◽  
Author(s):  
James D.P. Rhodes ◽  
Davide Mazza ◽  
Kim A. Nasmyth ◽  
Stephan Uphoff
Keyword(s):  
Single Molecule ◽  
Sister Chromatid ◽  
Fluorescence Recovery After Photobleaching ◽  
Sister Chromatid Cohesion ◽  
Dna Looping ◽  
Cohesin Complex ◽  
Single Molecule Tracking ◽  
Loading Function ◽  
Stop And Go ◽  
Chromatid Cohesion

AbstractThe cohesin complex mediates DNA-DNA interactions both between (sister chromatid cohesion) and within chromosomes (DNA looping) via a process thought to involve entrapment of DNAs within its tripartite ring. It has been suggested that intra- chromosome loops are generated through processive extrusion of DNAs through the lumen of cohesin’s ring. Scc2 (Nipbl) is essential for loading cohesin onto chromosomes but not for maintaining sister chromatid cohesion following DNA replication. It has therefore been assumed that Scc2 is involved exclusively in the cohesin loading process. However, it is possible that the stimulation of cohesin’s ABC-like ATPase by Scc2 also has a post-loading function, for example driving loop extrusion. Using fluorescence recovery after photobleaching (FRAP) and single-molecule tracking, we show that Scc2 binds dynamically to chromatin, principally through an association with cohesin. Scc2’s movement within chromatin is consistent with a “stop-and-go” or “hopping” motion. We suggest that a low diffusion coefficient, a low stoichiometry relative to cohesin, and a high affinity for chromosomal cohesin enables Scc2 to move rapidly from one chromosomal cohesin complex to another, performing a function distinct from loading.

scholarly journals Pds5p regulates the maintenance of sister chromatid cohesion and is sumoylated to promote the dissolution of cohesion

2003 ◽  
Vol 163 (4) ◽  
pp. 729-741 ◽  
Author(s):  
Kristen Stead ◽  
Cristina Aguilar ◽  
Theresa Hartman ◽  
Melissa Drexel ◽  
Pamela Meluh ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Temperature Sensitivity ◽  
Sister Chromatid ◽  
Sister Chromatid Cohesion ◽  
Cohesin Complex ◽  
Chromatid Cohesion ◽  
Chromosomal Loci

Pds5p and the cohesin complex are required for sister chromatid cohesion and localize to the same chromosomal loci over the same cell cycle window. However, Pds5p and the cohesin complex likely have distinct roles in cohesion. We report that pds5 mutants establish cohesion, but during mitosis exhibit precocious sister dissociation. Thus, unlike the cohesin complex, which is required for cohesion establishment and maintenance, Pds5p is required only for maintenance. We identified SMT4, which encodes a SUMO isopeptidase, as a high copy suppressor of both the temperature sensitivity and precocious sister dissociation of pds5 mutants. In contrast, SMT4 does not suppress temperature sensitivity of cohesin complex mutants. Pds5p is SUMO conjugated, with sumoylation peaking during mitosis. SMT4 overexpression reduces Pds5p sumoylation, whereas smt4 mutants have increased Pds5p sumoylation. smt4 mutants were previously shown to be defective in cohesion maintenance during mitosis. These data provide the first link between a protein required for cohesion, Pds5p, and sumoylation, and suggest that Pds5p sumoylation promotes the dissolution of cohesion.

scholarly journals Hardwired synthetic lethality within the cohesin complex in human cancer cells

2017 ◽  
Author(s):  
Petra van der Lelij ◽  
Simone Lieb ◽  
Julian Jude ◽  
Gordana Wutz ◽  
Catarina P. Santos ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Cancer Cells ◽  
Sister Chromatid ◽  
Sister Chromatid Cohesion ◽  
Cohesin Complex ◽  
Wild Type ◽  
Synthetic Lethal ◽  
Recurrent Mutations ◽  
Wide Range ◽  
Chromatid Cohesion

AbstractRecent genome analyses have identified recurrent mutations in the cohesin complex in a wide range of human cancers. Here we demonstrate that the most frequently mutated subunit of the cohesin complex, STAG2, displays a strong synthetic lethal interaction with its paralog STAG1. Mechanistically, STAG1 loss abrogates sister chromatid cohesion in STAG2 mutated but not in wild-type cells leading to mitotic catastrophe, defective cell division and apoptosis. STAG1 inactivation inhibits the proliferation of STAG2 mutated but not wild-type bladder cancer and Ewing sarcoma cell lines. Restoration of STAG2 expression in a mutated bladder cancer model alleviates the dependency on STAG1. Thus, STAG1 and STAG2 act redundantly to support sister chromatid cohesion and cell survival. STAG1 represents a hardwired, context independent vulnerability of cancer cells carrying mutations in the major emerging tumor suppressor STAG2. Exploiting synthetic lethal interactions to target recurrent cohesin mutations in cancer, e.g. by inhibiting STAG1, holds the promise for the development of selective therapeutics.

scholarly journals Synthetic lethality between the cohesin subunits STAG1 and STAG2 in diverse cancer contexts

2017 ◽  
Author(s):  
Petra van der Lelij ◽  
Simone Lieb ◽  
Julian Jude ◽  
Gordana Wutz ◽  
Catarina P. Santos ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Sister Chromatid ◽  
Synthetic Lethality ◽  
Sister Chromatid Cohesion ◽  
Cohesin Complex ◽  
Wild Type ◽  
Synthetic Lethal ◽  
Recurrent Mutations ◽  
Wide Range ◽  
Chromatid Cohesion

AbstractRecent genome analyses have identified recurrent mutations in the cohesin complex in a wide range of human cancers. Here we demonstrate that the most frequently mutated subunit of the cohesin complex, STAG2, displays a strong synthetic lethal interaction with its paralog STAG1. Mechanistically, STAG1 loss abrogates sister chromatid cohesion in STAG2 mutated but not in wild-type cells leading to mitotic catastrophe, defective cell division and apoptosis. STAG1 inactivation inhibits the proliferation of STAG2 mutated but not wild-type bladder cancer and Ewing sarcoma cell lines. Restoration of STAG2 expression in a mutated bladder cancer model alleviates the dependency on STAG1. Thus, STAG1 and STAG2 support sister chromatid cohesion to redundantly ensure cell survival. STAG1 represents a vulnerability of cancer cells carrying mutations in the major emerging tumor suppressor STAG2 across different cancer contexts. Exploiting synthetic lethal interactions to target recurrent cohesin mutations in cancer, e.g. by inhibiting STAG1, holds the promise for the development of selective therapeutics.

scholarly journals Saccharomyces cerevisiae CTF18 and CTF4 Are Required for Sister Chromatid Cohesion

2001 ◽  
Vol 21 (9) ◽  
pp. 3144-3158 ◽  
Author(s):  
Joseph S. Hanna ◽  
Evgueny S. Kroll ◽  
Victoria Lundblad ◽  
Forrest A. Spencer
Keyword(s):  
Sister Chromatid ◽  
Replication Fork ◽  
Spindle Assembly Checkpoint ◽  
Budding Yeast ◽  
Sister Chromatid Cohesion ◽  
Nuclear Antigen ◽  
Chromatid Cohesion ◽  
Core Components ◽  
Proliferating Cell

ABSTRACT CTF4 and CTF18 are required for high-fidelity chromosome segregation. Both exhibit genetic and physical ties to replication fork constituents. We find that absence of eitherCTF4 or CTF18 causes sister chromatid cohesion failure and leads to a preanaphase accumulation of cells that depends on the spindle assembly checkpoint. The physical and genetic interactions between CTF4, CTF18, and core components of replication fork complexes observed in this study and others suggest that both gene products act in association with the replication fork to facilitate sister chromatid cohesion. We find that Ctf18p, anRFC1-like protein, directly interacts with Rfc2p, Rfc3p, Rfc4p, and Rfc5p. However, Ctf18p is not a component of biochemically purified proliferating cell nuclear antigen loading RF-C, suggesting the presence of a discrete complex containing Ctf18p, Rfc2p, Rfc3p, Rfc4p, and Rfc5p. Recent identification and characterization of the budding yeast polymerase κ, encoded by TRF4, strongly supports a hypothesis that the DNA replication machinery is required for proper sister chromatid cohesion. Analogous to the polymerase switching role of the bacterial and human RF-C complexes, we propose that budding yeast RF-CCTF18 may be involved in a polymerase switch event that facilities sister chromatid cohesion. The requirement for CTF4 and CTF18 in robust cohesion identifies novel roles for replication accessory proteins in this process.

scholarly journals Interallelic complementation provides functional evidence for cohesin–cohesin interactions on DNA

2015 ◽  
Vol 26 (23) ◽  
pp. 4224-4235 ◽  
Author(s):  
Thomas Eng ◽  
Vincent Guacci ◽  
Douglas Koshland
Keyword(s):  
Sister Chromatid ◽  
Single Copy ◽  
Sister Chromatid Cohesion ◽  
Multiple Roles ◽  
Restrictive Temperature ◽  
Cohesin Complex ◽  
Chromosome Architecture ◽  
Sister Chromatids ◽  
Chromatid Cohesion ◽  
Interallelic Complementation

The cohesin complex (Mcd1p, Smc1p, Smc3p, and Scc3p) has multiple roles in chromosome architecture, such as promoting sister chromatid cohesion, chromosome condensation, DNA repair, and transcriptional regulation. The prevailing embrace model for sister chromatid cohesion posits that a single cohesin complex entraps both sister chromatids. We report interallelic complementation between pairs of nonfunctional mcd1 alleles (mcd1-1 and mcd1-Q266) or smc3 alleles (smc3-42 and smc3-K113R). Cells bearing individual mcd1 or smc3 mutant alleles are inviable and defective for both sister chromatid cohesion and condensation. However, cells coexpressing two defective mcd1 or two defective smc3 alleles are viable and have cohesion and condensation. Because cohesin contains only a single copy of Smc3p or Mcd1p, these examples of interallelic complementation must result from interplay or communication between the two defective cohesin complexes, each harboring one of the mutant allele products. Neither mcd1-1p nor smc3-42p is bound to chromosomes when expressed individually at its restrictive temperature. However, their chromosome binding is restored when they are coexpressed with their chromosome-bound interallelic complementing partner. Our results support a mechanism by which multiple cohesin complexes interact on DNA to mediate cohesion and condensation.

scholarly journals Cohesin Associates with Spindle Poles in a Mitosis-specific Manner and Functions in Spindle Assembly in Vertebrate Cells

2009 ◽  
Vol 20 (5) ◽  
pp. 1289-1301 ◽  
Author(s):  
Xiangduo Kong ◽  
Alexander R. Ball ◽  
Eiichiro Sonoda ◽  
Jie Feng ◽  
Shunichi Takeda ◽  
...  
Keyword(s):  
Chromosome Pairing ◽  
Sister Chromatid ◽  
Spindle Assembly ◽  
Sister Chromatid Cohesion ◽  
S Phase ◽  
Mitotic Apparatus ◽  
Spindle Poles ◽  
Chromatid Cohesion ◽  
Specific Manner

Cohesin is an essential protein complex required for sister chromatid cohesion. Cohesin associates with chromosomes and establishes sister chromatid cohesion during interphase. During metaphase, a small amount of cohesin remains at the chromosome-pairing domain, mainly at the centromeres, whereas the majority of cohesin resides in the cytoplasm, where its functions remain unclear. We describe the mitosis-specific recruitment of cohesin to the spindle poles through its association with centrosomes and interaction with nuclear mitotic apparatus protein (NuMA). Overexpression of NuMA enhances cohesin accumulation at spindle poles. Although transient cohesin depletion does not lead to visible impairment of normal spindle formation, recovery from nocodazole-induced spindle disruption was significantly impaired. Importantly, selective blocking of cohesin localization to centromeres, which disrupts centromeric sister chromatid cohesion, had no effect on this spindle reassembly process, clearly separating the roles of cohesin at kinetochores and spindle poles. In vitro, chromosome-independent spindle assembly using mitotic extracts was compromised by cohesin depletion, and it was rescued by addition of cohesin that was isolated from mitotic, but not S phase, cells. The combined results identify a novel spindle-associated role for human cohesin during mitosis, in addition to its function at the centromere/kinetochore regions.

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