scholarly journals Novel Response to Microtubule Perturbation in Meiosis

2005 ◽  
Vol 25 (11) ◽  
pp. 4767-4781 ◽  
Author(s):  
Andreas Hochwagen ◽  
Gunnar Wrobel ◽  
Marie Cartron ◽  
Philippe Demougin ◽  
Christa Niederhauser-Wiederkehr ◽  
...  

ABSTRACT During the mitotic cell cycle, microtubule depolymerization leads to a cell cycle arrest in metaphase, due to activation of the spindle checkpoint. Here, we show that under microtubule-destabilizing conditions, such as low temperature or the presence of the spindle-depolymerizing drug benomyl, meiotic budding yeast cells arrest in G1 or G2, instead of metaphase. Cells arrest in G1 if microtubule perturbation occurs as they enter the meiotic cell cycle and in G2 if cells are already undergoing premeiotic S phase. Concomitantly, cells down-regulate genes required for cell cycle progression, meiotic differentiation, and spore formation in a highly coordinated manner. Decreased expression of these genes is likely to be responsible for halting both cell cycle progression and meiotic development. Our results point towards the existence of a novel surveillance mechanism of microtubule integrity that may be particularly important during specialized cell cycles when coordination of cell cycle progression with a developmental program is necessary.

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Ufuk Günesdogan ◽  
Herbert Jäckle ◽  
Alf Herzig

Eukaryotes package DNA into nucleosomes that contain a core of histone proteins. During DNA replication, nucleosomes are disrupted and re-assembled with newly synthesized histones and DNA. Despite much progress, it is still unclear why higher eukaryotes contain multiple core histone genes, how chromatin assembly is controlled, and how these processes are coordinated with cell cycle progression. We used a histone null mutation of Drosophila melanogaster to show that histone supply levels, provided by a defined number of transgenic histone genes, regulate the length of S phase during the cell cycle. Lack of de novo histone supply not only extends S phase, but also causes a cell cycle arrest during G2 phase, and thus prevents cells from entering mitosis. Our results suggest a novel cell cycle surveillance mechanism that monitors nucleosome assembly without involving the DNA repair pathways and exerts its effect via suppression of CDC25 phosphatase String expression.


2020 ◽  
Vol 48 (16) ◽  
pp. 9067-9081
Author(s):  
Jonathan M Geisinger ◽  
Tim Stearns

Abstract While the mechanism of CRISPR/Cas9 cleavage is understood, the basis for the large variation in mutant recovery for a given target sequence between cell lines is much less clear. We hypothesized that this variation may be due to differences in how the DNA damage response affects cell cycle progression. We used incorporation of EdU as a marker of cell cycle progression to analyze the response of several human cell lines to CRISPR/Cas9 treatment with a single guide directed to a unique locus. Cell lines with functionally wild-type TP53 exhibited higher levels of cell cycle arrest compared to lines without. Chemical inhibition of TP53 protein combined with TP53 and RB1 transcript silencing alleviated induced arrest in TP53+/+ cells. Using dCas9, we determined this arrest is driven in part by Cas9 binding to DNA. Additionally, wild-type Cas9 induced fewer 53BP1 foci in TP53+/+ cells compared to TP53−/− cells and DD-Cas9, suggesting that differences in break sensing are responsible for cell cycle arrest variation. We conclude that CRISPR/Cas9 treatment induces a cell cycle arrest dependent on functional TP53 as well as Cas9 DNA binding and cleavage. Our findings suggest that transient inhibition of TP53 may increase genome editing recovery in primary and TP53+/+ cell lines.


1998 ◽  
Vol 9 (5) ◽  
pp. 1065-1080 ◽  
Author(s):  
Kenji Kitamura ◽  
Hiromi Maekawa ◽  
Chikashi Shimoda

When proliferating fission yeast cells are exposed to nitrogen starvation, they initiate conjugation and differentiate into ascospores. Cell cycle arrest in the G1-phase is one of the prerequisites for cell differentiation, because conjugation occurs only in the pre-Start G1-phase. The role ofste9 + in the cell cycle progression was investigated. Ste9 is a WD-repeat protein that is highly homologous to Hct1/Cdh1 and Fizzy-related. The ste9 mutants were sterile because they were defective in cell cycle arrest in the G1-phase upon starvation. Sterility was partially suppressed by the mutation in cig2 that encoded the major G1/S cyclin. Although cells lacking Ste9 function grow normally, the ste9 mutation was synthetically lethal with the wee1 mutation. In the double mutants ofste9 cdc10 ts, cells arrested in G1-phase at the restrictive temperature, but the level of mitotic cyclin (Cdc13) did not decrease. In these cells, abortive mitosis occurred from the pre-Start G1-phase. Overexpression of Ste9 decreased the Cdc13 protein level and the H1-histone kinase activity. In these cells, mitosis was inhibited and an extra round of DNA replication occurred. Ste9 regulates G1 progression possibly by controlling the amount of the mitotic cyclin in the G1-phase.


1996 ◽  
Vol 133 (6) ◽  
pp. 1307-1319 ◽  
Author(s):  
K Song ◽  
K E Mach ◽  
C Y Chen ◽  
T Reynolds ◽  
C F Albright

A novel gene, designated byr4, was identified in Schizosaccharomyces pombe that affects the mitotic cell cycle and shows genetic interactions with the ras1 signaling pathways. Null alleles of byr4 cause cell cycle arrest in late mitosis and permit multiple rounds of septation. The multiple septa typically divide two nuclei, but the nuclei frequently do not stain equally with 4',6-diamidino-2-phenylindole (DAPI), suggesting that byr4 is required for proper karyokinesis. Overexpression of byr4 inhibits cytokinesis, but cell cycle progression continues leading to multinucleate cells. When byr4 is overexpressed, the early steps in the cytokinesis pathway, including formation of the medial F-actin ring, occur normally; however, the later steps in the pathway, including contraction of the F-actin ring, septation, and rearrangement of the medial F-actin following mitosis, rarely occur, byr4 shows two genetic interactions with ras1. The inhibition of cytokinesis by byr4 overexpression was exacerbated by null alleles of ras1 and scd1, suggesting a link between pathways needed for cell polarity and cytokinesis. Overexpression of byr4 also partially bypasses the need for ras1 for sporulation. The electrophoretic mobility of the byr4 protein varied in response to mutants that perturb cytokinesis and karyokinesis, suggesting interactions between byr4 and these gene products. A more rapidly migrating byr4 protein was found in cells with mutations in cdc16, which undergo repeated septation, and in cdc15, which fail to form a medial F-actin ring in mitosis. A slower migrating byr4 protein was found in cells with a mutation in the beta-tubulin gene, which arrests cells at the metaphase-anaphase transition.


2019 ◽  
Author(s):  
Jonathan M. Geisinger ◽  
Tim Stearns

ABSTRACTWhile the mechanism of CRISPR/Cas9 cleavage is understood, the large variation in mutant recovery for a given target sequence between cell lines is much less clear. We hypothesized that this variation may be due to differences in how the DNA damage response affects cell cycle progression. We used incorporation of EdU as a marker of cell cycle progression to analyze the response of several human cell lines to CRISPR/Cas9 treatment with a single guide directed to a unique locus. Cell lines with functionally wild-type TP53 exhibited higher levels of cell cycle arrest compared to lines without. Chemical inhibition of TP53 protein combined with TP53 and RB1 transcript silencing alleviated induced arrest in TP53+/+ cells. This arrest is driven in part by Cas9 binding to DNA. Additionally, wild-type Cas9 induced fewer 53BP1 foci in TP53+/+ cells compared to TP53−/− cells, suggesting that differences in break sensing are responsible for cell cycle arrest variation. We conclude that CRISPR/Cas9 treatment induces a cell cycle arrest dependent on functional TP53 as well as Cas9 DNA binding and cleavage. Our findings suggest that transient inhibition of TP53 may increase genome editing efficiency in primary and TP53+/+ cell lines.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Pan Wang ◽  
Sheng Gong ◽  
Jinyu Pan ◽  
Junwei Wang ◽  
Dewei Zou ◽  
...  

AbstractThere exists a consensus that combining hyperbaric oxygen (HBO) and chemotherapy promotes chemotherapy sensitivity in GBM cells. However, few studies have explored the mechanism involved. HIF1α and HIF2α are the two main molecules that contribute to GBM malignant progression by inhibiting apoptosis or maintaining stemness under hypoxic conditions. Moreover, Sox2, a marker of stemness, also contributes to GBM malignant progression through stemness maintenance or cell cycle arrest. Briefly, HIF1α, HIF2α and Sox2 are highly expressed under hypoxia and contribute to GBM growth and chemoresistance. However, after exposure to HBO for GBM, whether the expression of the above factors is decreased, resulting in chemosensitization, remains unknown. Therefore, we performed a series of studies and determined that the expression of HIF1α, HIF2α and Sox2 was decreased after HBO and that HBO promoted GBM cell proliferation through cell cycle progression, albeit with a decrease in stemness, thus contributing to chemosensitization via the inhibition of HIF1α/HIF2α-Sox2.


2010 ◽  
Vol 84 (24) ◽  
pp. 12832-12840 ◽  
Author(s):  
Yuan He ◽  
Ke Xu ◽  
Bjoern Keiner ◽  
Jianfang Zhou ◽  
Volker Czudai ◽  
...  

ABSTRACT Many viruses interact with the host cell division cycle to favor their own growth. In this study, we examined the ability of influenza A virus to manipulate cell cycle progression. Our results show that influenza A virus A/WSN/33 (H1N1) replication results in G0/G1-phase accumulation of infected cells and that this accumulation is caused by the prevention of cell cycle entry from G0/G1 phase into S phase. Consistent with the G0/G1-phase accumulation, the amount of hyperphosphorylated retinoblastoma protein, a necessary active form for cell cycle progression through late G1 into S phase, decreased after infection with A/WSN/33 (H1N1) virus. In addition, other key molecules in the regulation of the cell cycle, such as p21, cyclin E, and cyclin D1, were also changed and showed a pattern of G0/G1-phase cell cycle arrest. It is interesting that increased viral protein expression and progeny virus production in cells synchronized in the G0/G1 phase were observed compared to those in either unsynchronized cells or cells synchronized in the G2/M phase. G0/G1-phase cell cycle arrest is likely a common strategy, since the effect was also observed in other strains, such as H3N2, H9N2, PR8 H1N1, and pandemic swine H1N1 viruses. These findings, in all, suggest that influenza A virus may provide favorable conditions for viral protein accumulation and virus production by inducing a G0/G1-phase cell cycle arrest in infected cells.


2012 ◽  
Vol 80 (4) ◽  
pp. 1467-1478 ◽  
Author(s):  
Carolina Coelho ◽  
Lydia Tesfa ◽  
Jinghang Zhang ◽  
Johanna Rivera ◽  
Teresa Gonçalves ◽  
...  

ABSTRACTWe investigated the outcome of the interaction ofCryptococcus neoformanswith murine macrophages using laser scanning cytometry (LSC). Previous results in our lab had shown that phagocytosis ofC. neoformanspromoted cell cycle progression. LSC allowed us to simultaneously measure the phagocytic index, macrophage DNA content, and 5-ethynyl-2′-deoxyuridine (EdU) incorporation such that it was possible to study host cell division as a function of phagocytosis. LSC proved to be a robust, reliable, and high-throughput method for quantifying phagocytosis. Phagocytosis ofC. neoformanspromoted cell cycle progression, but infected macrophages were significantly less likely to complete mitosis. Hence, we report a new cytotoxic effect associated with intracellularC. neoformansresidence that manifested itself in impaired cell cycle completion as a consequence of a block in the G2/M stage of the mitotic cell cycle. Cell cycle arrest was not due to increased cell membrane permeability or DNA damage. We investigated alveolar macrophage replicationin vivoand demonstrated that these cells are capable of low levels of cell division in the presence or absence ofC. neoformansinfection. In summary, we simultaneously studied phagocytosis, the cell cycle state of the host cell and pathogen-mediated cytotoxicity, and our results demonstrate a new cytotoxic effect ofC. neoformansinfection on murine macrophages: fungus-induced cell cycle arrest. Finally, we provide evidence for alveolar macrophage proliferationin vivo.


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