scholarly journals Physically asymmetric division of the C. elegans zygote ensures invariably successful embryogenesis

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Radek Jankele ◽  
Rob Jelier ◽  
Pierre Gönczy
Keyword(s):  
Cell Fate ◽  
Cell Cycle Progression ◽  
Cell Lineage ◽  
External Compression ◽  
Cycle Progression ◽  
Spindle Positioning ◽  
C Elegans ◽  
Daughter Cells ◽  
Asymmetric Divisions ◽  
Cell Positioning

Asymmetric divisions that yield daughter cells of different sizes are frequent during early embryogenesis, but the importance of such a physical difference for successful development remains poorly understood. Here, we investigated this question using the first division ofCaenorhabditis elegansembryos, which yields a large AB cell and a small P1cell. We equalized AB and P1sizes using acute genetic inactivation or optogenetic manipulation of the spindle positioning protein LIN-5. We uncovered that only some embryos tolerated equalization, and that there was a size asymmetry threshold for viability. Cell lineage analysis of equalized embryos revealed an array of defects, including faster cell cycle progression in P1descendants, as well as defects in cell positioning, division orientation, and cell fate. Moreover, equalized embryos were more susceptible to external compression. Overall, we conclude that unequal first cleavage is essential for invariably successful embryonic development ofC. elegans.

scholarly journals Physically asymmetric division of the C. elegans zygote ensures invariably successful embryogenesis

2021 ◽  
Author(s):  
Radek Jankele ◽  
Rob Jelier ◽  
Pierre Gönczy
Keyword(s):  
Cell Fate ◽  
Cell Cycle Progression ◽  
Cell Lineage ◽  
External Compression ◽  
Cycle Progression ◽  
Spindle Positioning ◽  
C Elegans ◽  
Daughter Cells ◽  
Asymmetric Divisions ◽  
Cell Positioning

Asymmetric divisions that yield daughter cells of different sizes are frequent during early embryogenesis, but the importance of such a physical difference for successful development remains poorly understood. Here, we investigated this question using the first division of C. elegans embryos, which yields a large AB cell and a small P1 cell. We equalized AB and P1 sizes using acute genetic inactivation or optogenetic manipulation of the spindle positioning protein LIN-5. We uncovered that only some embryos tolerated equalization and that there was a size asymmetry threshold for viability. Cell lineage analysis of equalized embryos revealed an array of defects, including faster cell cycle progression in P1 descendants, as well as defects in cell positioning, division orientation, and cell fate. Moreover, equalized embryos were more susceptible to external compression. Overall, we conclude that unequal first cleavage is essential for invariably successful embryonic development of C. elegans.

scholarly journals Cyclin E and CDK-2 regulate proliferative cell fate and cell cycle progression in the C. elegans germline

Development ◽  
2011 ◽  
Vol 138 (11) ◽  
pp. 2223-2234 ◽  
Author(s):  
P. M. Fox ◽  
V. E. Vought ◽  
M. Hanazawa ◽  
M.-H. Lee ◽  
E. M. Maine ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Fate ◽  
Cell Cycle Progression ◽  
Cyclin E ◽  
Cycle Progression ◽  
C Elegans ◽  
Proliferative Cell

scholarly journals Cellular responses to a prolonged delay in mitosis are determined by a DNA damage response controlled by Bcl-2 family proteins

Open Biology ◽  
2015 ◽  
Vol 5 (3) ◽  
pp. 140156 ◽  
Author(s):  
Didier J. Colin ◽  
Karolina O. Hain ◽  
Lindsey A. Allan ◽  
Paul R. Clarke
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Protein Kinases ◽  
Cell Fate ◽  
Dna Damage Response ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Anti Cancer ◽  
Damage Response ◽  
Microtubule Poisons

Anti-cancer drugs that disrupt mitosis inhibit cell proliferation and induce apoptosis, although the mechanisms of these responses are poorly understood. Here, we characterize a mitotic stress response that determines cell fate in response to microtubule poisons. We show that mitotic arrest induced by these drugs produces a temporally controlled DNA damage response (DDR) characterized by the caspase-dependent formation of γH2AX foci in non-apoptotic cells. Following exit from a delayed mitosis, this initial response results in activation of DDR protein kinases, phosphorylation of the tumour suppressor p53 and a delay in subsequent cell cycle progression. We show that this response is controlled by Mcl-1, a regulator of caspase activation that becomes degraded during mitotic arrest. Chemical inhibition of Mcl-1 and the related proteins Bcl-2 and Bcl-x L by a BH3 mimetic enhances the mitotic DDR, promotes p53 activation and inhibits subsequent cell cycle progression. We also show that inhibitors of DDR protein kinases as well as BH3 mimetics promote apoptosis synergistically with taxol (paclitaxel) in a variety of cancer cell lines. Our work demonstrates the role of mitotic DNA damage responses in determining cell fate in response to microtubule poisons and BH3 mimetics, providing a rationale for anti-cancer combination chemotherapies.

Meiotic cycle checkpoints in mammalian oocytes

Zygote ◽  
1994 ◽  
Vol 2 (4) ◽  
pp. 351-354 ◽  
Author(s):  
Josef Fulka ◽  
Judy Bradshaw ◽  
Robert Moor
Keyword(s):  
Chromosome Segregation ◽  
Cell Cycle Progression ◽  
Mitotic Cell ◽  
Mitotic Cell Cycle ◽  
Cycle Progression ◽  
Daughter Cells ◽  
Chromosomal Segregation ◽  
Nuclear Events ◽  
Last Stage ◽  
Meiotic Cycle

Recent Spectacular achievements have enabled the identification of key molecules responsible for mitotic cell cycle progression through the stages of G1, the gap before DNA replication; S, the phase of DNA synthesis; G2, the gap before chromosome segregation; and M, mitosis itself. The last stage has been most intensively studied, where MPE, maturation promotion factor, has been found responsible for the nuclear events associated with chromosomal segregation and the prodcution of two identical daughter cells (see Murray & Hunt, 1993).

scholarly journals Myosin-driven peroxisome partitioning in S. cerevisiae

2009 ◽  
Vol 186 (4) ◽  
pp. 541-554 ◽  
Author(s):  
Andrei Fagarasanu ◽  
Fred D. Mast ◽  
Barbara Knoblach ◽  
Yui Jin ◽  
Matthew J. Brunner ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Molecular Motors ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Class V ◽  
Daughter Cells ◽  
Mother And Daughter ◽  
Specific Receptors ◽  
Cycle Dependent ◽  
Mother Cells

In Saccharomyces cerevisiae, the class V myosin motor Myo2p propels the movement of most organelles. We recently identified Inp2p as the peroxisome-specific receptor for Myo2p. In this study, we delineate the region of Myo2p devoted to binding peroxisomes. Using mutants of Myo2p specifically impaired in peroxisome binding, we dissect cell cycle–dependent and peroxisome partitioning–dependent mechanisms of Inp2p regulation. We find that although total Inp2p levels oscillate with the cell cycle, Inp2p levels on individual peroxisomes are controlled by peroxisome inheritance, as Inp2p aberrantly accumulates and decorates all peroxisomes in mother cells when peroxisome partitioning is abolished. We also find that Inp2p is a phosphoprotein whose level of phosphorylation is coupled to the cell cycle irrespective of peroxisome positioning in the cell. Our findings demonstrate that both organelle positioning and cell cycle progression control the levels of organelle-specific receptors for molecular motors to ultimately achieve an equidistribution of compartments between mother and daughter cells.

scholarly journals Centrosomes Enhance the Fidelity of Cytokinesis in Vertebrates and Are Required for Cell Cycle Progression

2001 ◽  
Vol 153 (1) ◽  
pp. 237-242 ◽  
Author(s):  
Alexey Khodjakov ◽  
Conly L. Rieder
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Somatic Cells ◽  
Spindle Pole ◽  
Primary Role ◽  
Mitotic Spindles ◽  
Cycle Progression ◽  
Daughter Cells ◽  
Cell Changes

When centrosomes are destroyed during prophase by laser microsurgery, vertebrate somatic cells form bipolar acentrosomal mitotic spindles (Khodjakov, A., R.W. Cole, B.R. Oakley, and C.L. Rieder. 2000. Curr. Biol. 10:59–67), but the fate of these cells is unknown. Here, we show that, although these cells lack the radial arrays of astral microtubules normally associated with each spindle pole, they undergo a normal anaphase and usually produce two acentrosomal daughter cells. Relative to controls, however, these cells exhibit a significantly higher (30–50%) failure rate in cytokinesis. This failure correlates with the inability of the spindle to properly reposition itself as the cell changes shape. Also, we destroyed just one centrosome during metaphase and followed the fate of the resultant acentrosomal and centrosomal daughter cells. Within 72 h, 100% of the centrosome-containing cells had either entered DNA synthesis or divided. By contrast, during this period, none of the acentrosomal cells had entered S phase. These data reveal that the primary role of the centrosome in somatic cells is not to form the spindle but instead to ensure cytokinesis and subsequent cell cycle progression.

Epigenetic dynamics across the cell cycle

2010 ◽  
Vol 48 ◽  
pp. 107-120 ◽  
Author(s):  
Tony Bou Kheir ◽  
Anders H. Lund
Keyword(s):  
Cell Cycle ◽  
Chromosome Segregation ◽  
Cell Cycle Progression ◽  
Current Knowledge ◽  
Chromatin Condensation ◽  
Chromatin Modifications ◽  
Cycle Progression ◽  
Daughter Cells ◽  
Mammalian Cell Cycle ◽  
Regulate Cell Cycle Progression

Progression of the mammalian cell cycle depends on correct timing and co-ordination of a series of events, which are managed by the cellular transcriptional machinery and epigenetic mechanisms governing genome accessibility. Epigenetic chromatin modifications are dynamic across the cell cycle, and are shown to influence and be influenced by cell-cycle progression. Chromatin modifiers regulate cell-cycle progression locally by controlling the expression of individual genes and globally by controlling chromatin condensation and chromosome segregation. The cell cycle, on the other hand, ensures a correct inheritance of epigenetic chromatin modifications to daughter cells. In this chapter, we summarize the current knowledge on the dynamics of epigenetic chromatin modifications during progression of the cell cycle.

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