scholarly journals CRISPR-Based DNA Imaging in Living Cells Reveals Cell Cycle-Dependent Chromosome Dynamics

2017 ◽  
Author(s):  
Hanhui Ma ◽  
Li-Chun Tu ◽  
Ardalan Naseri ◽  
Yu-Chieh Chung ◽  
David Grunwald ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Living Cells ◽  
Genomic Region ◽  
List Type ◽  
Relaxation Dynamic ◽  
Cycle Progression ◽  
Chromosome Dynamics ◽  
Chromosomal Loci ◽  
Dna Imaging

SUMMARYIn contrast to the well-studied condensation and folding of chromosomes during mitosis, their dynamics in interphase are less understood. We developed a sensitive, multicolor system, CRISPR-Sirius, allowing the real-time tracking of the dynamics of chromosomal loci. We tracked loci kilobases to megabases apart and found significant variation in the inter-locus distances of each pair, indicating differing degrees of DNA contortion. We resolved two distinct modes of dynamics of loci: saltatory local movements as well as translational movements of the domain. The magnitude of both of these modes of movements increased from early to late G1, whereas the translational movements were reduced in early S. The local fluctuations decreased slightly in early S and more markedly in mid-late S. These newly observed movements and their cell cycle-dependence are indicative of a hitherto unrecognized compaction-relaxation dynamic of the chromosomal fiber operating concurrently with changes in the extent of observed genomic domain movements.IN BRIEFDistinct chromosome folding and dynamics during cell cycle progression were dissected by CRISPR-Sirius DNA imaging in living cells.HIGHLIGHTSCRISPR-Sirius allows tracking of pairs of chromosomal loci having kilobase to megabase inter-locus distancesPair-wise tracking of loci allows measurement of both local and domain dynamicsChromosomal fiber relaxation is positively correlated with local dynamicsGenomic region size contributes to local and domain movementsDistinct chromosome dynamics were uncovered during cell cycle progression in interphase

scholarly journals Chromosome dynamics and spatial organization during the non-binary cell cycle of a predatory bacterium

2020 ◽  
Author(s):  
Jovana Kaljević ◽  
Terrens N. V. Saaki ◽  
Sander K. Govers ◽  
Ophélie Remy ◽  
Renske van Raaphorst ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Cell Cycle Progression ◽  
Spatial Organization ◽  
Chromosome Replication ◽  
Circular Chromosome ◽  
Cycle Progression ◽  
Bdellovibrio Bacteriovorus ◽  
Chromosome Dynamics ◽  
Complex Chromosome

AbstractIn bacteria, the dynamics of chromosome replication and segregation are tightly coordinated with cell cycle progression, and largely rely on specific spatiotemporal arrangement of the chromosome. Whereas these key processes are mostly investigated in species that divide by binary fission, they remain mysterious in bacteria producing larger number of descendants. Here, we establish the predatory bacterium Bdellovibrio bacteriovorus as a model to investigate the non-binary processing of a circular chromosome. Our data reveal its extreme compaction in a dense polarized nucleoid. We also show that a first binary-like cycle of replication and asymmetric segregation is followed by multiple asynchronous rounds of replication and progressive ParABS-dependent partitioning, uncoupled from cell division. Surprisingly, ParB localization at the centromere is cell-cycle regulated. Altogether, our findings support a model of complex chromosome choreography, leading to the generation of variable numbers of offspring, highlighting the adaptation of conserved mechanisms to achieve non-binary reproduction in bacteria.

scholarly journals A switch in cilia-mediated Hedgehog signaling controls muscle stem cell quiescence and cell cycle progression

2019 ◽  
Author(s):  
Sara Betania Cruz-Migoni ◽  
Kamalliawati Mohd Imran ◽  
Aysha Wahid ◽  
Oisharja Rahman ◽  
James Briscoe ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Stem Cell ◽  
Cell Cycle Progression ◽  
Ex Vivo ◽  
List Type ◽  
Quiescent State ◽  
Self Renewal ◽  
Cycle Progression

SummaryTissue homeostasis requires a tight control of stem cells to maintain quiescence in normal conditions, and ensure a balance between progenitor cell production and the need to preserve a stem cell pool in repair conditions. Using ex-vivo and in-vivo genetic approaches, we provide evidence that primary cilium-mediated repressive Hedgehog (Hh) signalling is required to maintain skeletal muscle stem cells (MuSCs) in a quiescent state. De-repression and further activation of Hh signalling initiates MuSC entry and progression through the cell cycle, and controls self-renewal to ensure efficient repair of injured muscles. We propose a model whereby disassembly of primary cilia upon MuSC activation induces a switch in Hh signalling from a repressive to active state that controls exit from quiescence. Positive Hh response in bi-potential muscle progenitor cells regulates also cell cycle progression and drives MuSC self-renewal. These findings identify Hh signalling as a major regulator of MuSC activity.HighlightsCilia-containing quiescent MuSCs are Hh signalling suppressedMuSC activation coincides with a switch to active Hh signallingSmo mutation delays cell cycle entry and progression, and causes impaired self-renewalPtch1 mutation promotes exit from quiescence, rapid cell cycle and increased self-renewalGraphical abstract

1955-P: GLP-1R Activation Attenuates Prostate Cancer Growth via Inhibiting Cell Cycle Progression

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 1955-P
Author(s):  
TORU SHIGEOKA ◽  
TAKASHI NOMIYAMA ◽  
TAKAKO KAWANAMI ◽  
YURIKO HAMAGUCHI ◽  
TOMOKO TANAKA ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Cancer Growth ◽  
Cycle Progression
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