scholarly journals Mechanical Mechanisms of Chromosome Segregation

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 465
Author(s):  
Maya I. Anjur-Dietrich ◽  
Colm P. Kelleher ◽  
Daniel J. Needleman
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Genetic Material ◽  
Evolutionary Genetics ◽  
Force Generation ◽  
Coarse Grained ◽  
Subcellular Structure ◽  
Daughter Cells ◽  
The Past ◽  
The Future

Chromosome segregation—the partitioning of genetic material into two daughter cells—is one of the most crucial processes in cell division. In all Eukaryotes, chromosome segregation is driven by the spindle, a microtubule-based, self-organizing subcellular structure. Extensive research performed over the past 150 years has identified numerous commonalities and contrasts between spindles in different systems. In this review, we use simple coarse-grained models to organize and integrate previous studies of chromosome segregation. We discuss sites of force generation in spindles and fundamental mechanical principles that any understanding of chromosome segregation must be based upon. We argue that conserved sites of force generation may interact differently in different spindles, leading to distinct mechanical mechanisms of chromosome segregation. We suggest experiments to determine which mechanical mechanism is operative in a particular spindle under study. Finally, we propose that combining biophysical experiments, coarse-grained theories, and evolutionary genetics will be a productive approach to enhance our understanding of chromosome segregation in the future.

scholarly journals Dem Anfang auf der Spur — die Suche nach DNA-Replikationsursprüngen

BIOspektrum ◽  
2021 ◽  
Vol 27 (3) ◽  
pp. 246-249
Author(s):  
Elisabeth Kruse ◽  
Stephan Hamperl
Keyword(s):  
Cell Division ◽  
Dna Synthesis ◽  
Genomic Dna ◽  
Genetic Material ◽  
Uniform Method ◽  
Replication Origins ◽  
Daughter Cells ◽  
Origins Of Replication ◽  
Mammalian Genomes ◽  
Comprehensive Manner

AbstractTimely and accurate duplication of DNA prior to cell division is a prerequisite for propagation of the genetic material to both daughter cells. DNA synthesis initiates at discrete sites, termed replication origins, and proceeds in a bidirectional manner until all genomic DNA is replicated. Despite the fundamental nature of these events, a uniform method that identifies origins of replication in a comprehensive manner is still missing. Here, we present currently available and discuss new approaches to map replication origins in mammalian genomes.

scholarly journals Cytokinesis in Eukaryotic Cells: The Furrow Complexity at a Glance

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 271 ◽  
Author(s):  
Roberta Fraschini
Keyword(s):  
Cell Division ◽  
Asymmetric Cell Division ◽  
Animal Cell ◽  
Genetic Material ◽  
Model Organism ◽  
Complex Phase ◽  
Daughter Cells ◽  
Viable Cells ◽  
A Cell ◽  
Duplication Cycle

The duplication cycle is the fascinating process that, starting from a cell, results in the formation of two daughter cells and it is essential for life. Cytokinesis is the final step of the cell cycle, it is a very complex phase, and is a concert of forces, remodeling, trafficking, and cell signaling. All of the steps of cell division must be properly coordinated with each other to faithfully segregate the genetic material and this task is fundamental for generating viable cells. Given the importance of this process, molecular pathways and proteins that are involved in cytokinesis are conserved from yeast to humans. In this review, we describe symmetric and asymmetric cell division in animal cell and in a model organism, budding yeast. In addition, we illustrate the surveillance mechanisms that ensure a proper cell division and discuss the connections with normal cell proliferation and organs development and with the occurrence of human diseases.

scholarly journals Recombination and chromosome segregation

2004 ◽  
Vol 359 (1441) ◽  
pp. 61-69 ◽  
Author(s):  
David J. Sherratt ◽  
Britta Søballe ◽  
François–Xavier Barre ◽  
Sergio Filipe ◽  
Ivy Lau ◽  
...  
Keyword(s):  
Cell Division ◽  
Homologous Recombination ◽  
Chromosome Segregation ◽  
Atp Hydrolysis ◽  
Daughter Cells ◽  
Recombination Proteins ◽  
Recombination System ◽  
Associated Proteins ◽  
Stalled Replication Forks ◽  
Circular Chromosomes

The duplication of DNA and faithful segregation of newly replicated chromosomes at cell division is frequently dependent on recombinational processes. The rebuilding of broken or stalled replication forks is universally dependent on homologous recombination proteins. In bacteria with circular chromosomes, crossing over by homologous recombination can generate dimeric chromosomes, which cannot be segregated to daughter cells unless they are converted to monomers before cell division by the conserved Xer site–specific recombination system. Dimer resolution also requires FtsK, a division septum–located protein, which coordinates chromosome segregation with cell division, and uses the energy of ATP hydrolysis to activate the dimer resolution reaction. FtsK can also translocate DNA, facilitate synapsis of sister chromosomes and minimize entanglement and catenation of newly replicated sister chromosomes. The visualization of the replication/recombination–associated proteins, RecQ and RarA, and specific genes within living Escherichia coli cells, reveals further aspects of the processes that link replication with recombination, chromosome segregation and cell division, and provides new insight into how these may be coordinated.

scholarly journals Chromosome segregation drives division site selection inStreptococcus pneumoniae

2016 ◽  
Author(s):  
Renske van Raaphorst ◽  
Morten Kjos ◽  
Jan-Willem Veening
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Site Selection ◽  
Bacterial Cell Division ◽  
Division Plane ◽  
Canonical Systems ◽  
Daughter Cells ◽  
Division Site ◽  
Additional Protein ◽  
Site Control

AbstractAccurate spatial and temporal positioning of the tubulin-like protein FtsZ is key for proper bacterial cell division.Streptococcus pneumoniae(pneumococcus) is an oval-shaped, symmetrically dividing human pathogen lacking the canonical systems for division site control (nucleoid occlusion and the Min-system). Recently, the early division protein MapZ was identified and implicated in pneumococcal division site selection. We show that MapZ is important for proper division plane selection; thus the question remains what drives pneumococcal division site selection. By mapping the cell cycle in detail, we show that directly after replication both chromosomal origin regions localize to the future cell division sites, prior to FtsZ. Perturbing the longitudinal chromosomal organization by mutating the condensin SMC, by CRISPR/Cas9-mediated chromosome cutting or by poisoning DNA decatenation resulted in mistiming of MapZ and FtsZ positioning and subsequent cell elongation. Together, we demonstrate an intimate relationship between DNA replication, chromosome segregation and division site selection in the pneumococcus, providing a simple way to ensure equally sized daughter cells without the necessity for additional protein factors.

scholarly journals The Unresolved Problem of DNA Bridging

Genes ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 623 ◽  
Author(s):  
María Fernández-Casañas ◽  
Kok-Lung Chan
Keyword(s):  
Chromosome Segregation ◽  
Genome Stability ◽  
Genetic Material ◽  
Genome Integrity ◽  
Cellular Division ◽  
Daughter Cells ◽  
Dna Replication And Repair ◽  
A Cell ◽  
Chromosome Separation ◽  
Last Stage

Accurate duplication and transmission of identical genetic information into offspring cells lies at the heart of a cell division cycle. During the last stage of cellular division, namely mitosis, the fully replicated DNA molecules are condensed into X-shaped chromosomes, followed by a chromosome separation process called sister chromatid disjunction. This process allows for the equal partition of genetic material into two newly born daughter cells. However, emerging evidence has shown that faithful chromosome segregation is challenged by the presence of persistent DNA intertwining structures generated during DNA replication and repair, which manifest as so-called ultra-fine DNA bridges (UFBs) during anaphase. Undoubtedly, failure to disentangle DNA linkages poses a severe threat to mitosis and genome integrity. This review will summarize the possible causes of DNA bridges, particularly sister DNA inter-linkage structures, in an attempt to explain how they may be processed and how they influence faithful chromosome segregation and the maintenance of genome stability.

scholarly journals Dynamics of Escherichia coli Chromosome Segregation during Multifork Replication

2007 ◽  
Vol 189 (23) ◽  
pp. 8660-8666 ◽  
Author(s):  
Henrik J. Nielsen ◽  
Brenda Youngren ◽  
Flemming G. Hansen ◽  
Stuart Austin
Keyword(s):  
Escherichia Coli ◽  
Cell Cycle ◽  
Growth Rate ◽  
Cell Division ◽  
Chromosome Segregation ◽  
Replication Forks ◽  
Daughter Cells ◽  
Initiation Of Replication ◽  
Replication Terminus ◽  
Multiple Replication

ABSTRACT Slowly growing Escherichia coli cells have a simple cell cycle, with replication and progressive segregation of the chromosome completed before cell division. In rapidly growing cells, initiation of replication occurs before the previous replication rounds are complete. At cell division, the chromosomes contain multiple replication forks and must be segregated while this complex pattern of replication is still ongoing. Here, we show that replication and segregation continue in step, starting at the origin and progressing to the replication terminus. Thus, early-replicated markers on the multiple-branched chromosomes continue to separate soon after replication to form separate protonucleoids, even though they are not segregated into different daughter cells until later generations. The segregation pattern follows the pattern of chromosome replication and does not follow the cell division cycle. No extensive cohesion of sister DNA regions was seen at any growth rate. We conclude that segregation is driven by the progression of the replication forks.

scholarly journals Concurrent processes setE. colicell division

2018 ◽  
Vol 4 (11) ◽  
pp. eaau3324 ◽  
Author(s):  
Gabriele Micali ◽  
Jacopo Grilli ◽  
Matteo Osella ◽  
Marco Cosentino Lagomarsino
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Single Cell ◽  
Chromosome Segregation ◽  
Genetic Material ◽  
Replication Initiation ◽  
Concurrent Processes ◽  
A Cell ◽  
Rate Limiting ◽  
Cell Data

A cell can divide only upon completion of chromosome segregation; otherwise, its daughters would lose genetic material. However, we do not know whether the partitioning of chromosomes is the key event for the decision to divide. We show how key trends in single-cell data reject the classic idea of replication-segregation as the rate-limiting process for cell division. Instead, the data agree with a model where two concurrent processes (setting replication initiation and interdivision time) set cell division on competing time scales. During each cell cycle, division is set by the slowest process (an “AND” gate). The concept of transitions between cell cycle stages as decisional processes integrating multiple inputs instead of cascading from orchestrated steps can affect the way we think of the cell cycle in general.

scholarly journals The Heritability of Replication Problems

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1464
Author(s):  
Jean-Sébastien Hoffmann
Keyword(s):  
Dna Replication ◽  
Cancer Progression ◽  
Genetic Material ◽  
Replication Timing ◽  
Cellular Responses ◽  
Replication Forks ◽  
Next Generation ◽  
Checkpoint Response ◽  
Daughter Cells ◽  
The Past

The major challenge of DNA replication is to provide daughter cells with intact and fully duplicated genetic material. However, various endogenous or environmental factors can slow down or stall DNA replication forks; these replication problems are known to fuel genomic instability and associated pathology, including cancer progression. Whereas the mechanisms emphasizing the source and the cellular responses of replicative problems have attracted much consideration over the past decade, the propagation through mitosis of genome modification and its heritability in daughter cells when the stress is not strong enough to provoke a checkpoint response in G2/M was much less documented. Some recent studies addressing whether low replication stress could impact the DNA replication program of the next generation of cells made the remarkable discovery that DNA damage can indeed be transmitted to daughter cells and can be processed in the subsequent S-phase, and that the replication timing program at a subset of chromosomal domains can also be impacted in the next generation of cells. Such a progression of replication problems into mitosis and daughter cells may appear counter-intuitive, but it could offer considerable advantages by alerting the next generation of cells of potentially risky loci and offering the possibility of an adaptive mechanism to anticipate a reiteration of problems, notably for cancer cells in the context of resistance to therapy.

scholarly journals Centromeric Non-Coding RNAs: Conservation and Diversity in Function

2020 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Takashi Ideue ◽  
Tokio Tani
Keyword(s):  
Chromosome Segregation ◽  
Genetic Material ◽  
Experimental Studies ◽  
Mitotic Chromosomes ◽  
Daughter Cells ◽  
Non Coding Rnas ◽  
Available Information

Chromosome segregation is strictly regulated for the proper distribution of genetic material to daughter cells. During this process, mitotic chromosomes are pulled to both poles by bundles of microtubules attached to kinetochores that are assembled on the chromosomes. Centromeres are specific regions where kinetochores assemble. Although these regions were previously considered to be silent, some experimental studies have demonstrated that transcription occurs in these regions to generate non-coding RNAs (ncRNAs). These centromeric ncRNAs (cenRNAs) are involved in centromere functions. Here, we describe the currently available information on the functions of cenRNAs in several species.

scholarly journals The nature of cell division forces in epithelial monolayers

2021 ◽  
Vol 220 (8) ◽  
Author(s):  
Vivek K. Gupta ◽  
Sungmin Nam ◽  
Donghyun Yim ◽  
Jaclyn Camuglia ◽  
Judy Lisette Martin ◽  
...  
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Morphological Changes ◽  
Tissue Growth ◽  
Force Generation ◽  
Model Organisms ◽  
Epithelial Monolayers ◽  
Dividing Cells ◽  
Division Axis ◽  
Universal Mechanism

Epithelial cells undergo striking morphological changes during division to ensure proper segregation of genetic and cytoplasmic materials. These morphological changes occur despite dividing cells being mechanically restricted by neighboring cells, indicating the need for extracellular force generation. Beyond driving cell division itself, forces associated with division have been implicated in tissue-scale processes, including development, tissue growth, migration, and epidermal stratification. While forces generated by mitotic rounding are well understood, forces generated after rounding remain unknown. Here, we identify two distinct stages of division force generation that follow rounding: (1) Protrusive forces along the division axis that drive division elongation, and (2) outward forces that facilitate postdivision spreading. Cytokinetic ring contraction of the dividing cell, but not activity of neighboring cells, generates extracellular forces that propel division elongation and contribute to chromosome segregation. Forces from division elongation are observed in epithelia across many model organisms. Thus, division elongation forces represent a universal mechanism that powers cell division in confining epithelia.

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