scholarly journals 2006 Cold Spring Harbor Cell Cycle Meeting Report: Before and After the Spindle Assembly Checkpoint—An APC/C Point of View

Cell Cycle ◽  
2006 ◽  
Vol 5 (18) ◽  
pp. 2168-2171 ◽  
Author(s):  
Armand de Gramont ◽  
Olivier Ganier ◽  
Orna Cohen-Fix
Keyword(s):  
Cell Cycle ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Cold Spring Harbor ◽  
Point Of View ◽  
Meeting Report ◽  
Before And After ◽  
Cold Spring

Comparison of the effects of BPA and BPAF on oocyte spindle assembly and polar body release in mice

Zygote ◽  
2015 ◽  
Vol 24 (2) ◽  
pp. 172-180 ◽  
Author(s):  
Kei Nakano ◽  
Manami Nishio ◽  
Norio Kobayashi ◽  
Yuuki Hiradate ◽  
Yumi Hoshino ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Oocyte Maturation ◽  
Spindle Assembly Checkpoint ◽  
Polar Body ◽  
Sharp Decrease ◽  
Spindle Assembly ◽  
Environmental Chemical ◽  
Cell Cycle Delay ◽  
A Cell

SummaryBisphenol AF (BPAF), a homolog of bisphenol A (BPA), is a widely used environmental chemical that has adverse effects on reproduction. The aim of this study was to analyse the effects of BPA and BPAF exposure on oocyte maturation in vitro. Oocytes were cultured in the presence of BPA or BPAF (2, 20, 50 or 100 μg/ml) for 18 h. At concentrations of 50 and 100 μg/ml, BPA and BPAF inhibited oocyte maturation, with BPAF treatment causing a sharp decrease in the number of oocytes reaching maturity. Oocytes were exposed to BPA or BPAF at 2 μg/ml and cultured for different durations (6, 9, 12, 15 or 18 h). Both BPAF and BPA caused a cell cycle delay under these conditions. Oocytes cultured in the presence of BPA or BPAF (50 μg/ml) for 21 h were tested for the localization of α-tubulin and MAD2 using immunofluorescence. High concentrations of BPAF induced cell cycle arrest through the activation of the spindle assembly checkpoint. After 12 h of culture in BPAF (50 μg/ml), oocytes were transferred to control medium for 9 h. Only 63.3% oocytes treated in this manner progressed to metaphase II (MII). Oocytes exposed to high doses of BPA experienced a cell cycle delay, but managed to progress to MII when the culture period was prolonged. In addition, MAD2 was localized in the cytoplasm of these oocytes. In conclusion, both BPAF and BPA exposure affected oocyte maturation, however BPAF and BPA have differential effects on SAC activity.

scholarly journals The Interaction Between Ran and NTF2 is Required for Cell Cycle Progression

2000 ◽  
Vol 11 (8) ◽  
pp. 2617-2629 ◽  
Author(s):  
B. Booth Quimby ◽  
Cassandra A. Wilson ◽  
Anita H. Corbett
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Spindle Assembly Checkpoint ◽  
Cell Cycle Control ◽  
Spindle Assembly ◽  
Bound State ◽  
Small Gtpase ◽  
Temperature Sensitive ◽  
Dependent Manner

The small GTPase Ran is required for the trafficking of macromolecules into and out of the nucleus. Ran also has been implicated in cell cycle control, specifically in mitotic spindle assembly. In interphase cells, Ran is predominately nuclear and thought to be GTP bound, but it is also present in the cytoplasm, probably in the GDP-bound state. Nuclear transport factor 2 (NTF2) has been shown to import RanGDP into the nucleus. Here, we examine the in vivo role of NTF2 in Ran import and the effect that disruption of Ran imported into the nucleus has on the cell cycle. A temperature-sensitive (ts) mutant of Saccharomyces cerevisiae NTF2 that does not bind to Ran is unable to import Ran into the nucleus at the nonpermissive temperature. Moreover, when Ran is inefficiently imported into the nucleus, cells arrest in G2in aMAD2 checkpoint-dependent manner. These findings demonstrate that NTF2 is required to transport Ran into the nucleus in vivo. Furthermore, we present data that suggest that depletion of nuclear Ran triggers a spindle-assembly checkpoint-dependent cell cycle arrest.

scholarly journals TheSac3Homologueshd1Is Involved in Mitotic Progression in Mammalian Cells

2004 ◽  
Vol 279 (44) ◽  
pp. 46182-46190 ◽  
Author(s):  
Sefat-e- Khuda ◽  
Mikoto Yoshida ◽  
Yan Xing ◽  
Tatsuya Shimasaki ◽  
Motohiro Takeya ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Spindle Assembly Checkpoint ◽  
Fluorescent Protein ◽  
Spindle Assembly ◽  
Centrosome Duplication ◽  
Cycle Progression ◽  
M Phase ◽  
Green Fluorescent

SaccharomycesSac3 required for actin assembly was shown to be involved in DNA replication. Here, we studied the function of a mammalian homologue SHD1 in cell cycle progression. SHD1 is localized on centrosomes at interphase and at spindle poles and mitotic spindles, similar to α-tubulin, at M phase. RNA interference suppression of endogenousshd1caused defects in centrosome duplication and spindle formation displaying cells with a single apparent centrosome and down-regulated Mad2 expression, generating increased micronuclei. Conversely, increased expression of SHD1 by DNA transfection withshd1-green fluorescent protein (gfp) vector for a fusion protein of SHD1 and GFP caused abnormalities in centrosome duplication displaying cells with multiple centrosomes and deregulated spindle assembly with up-regulated Mad2 expression until anaphase, generating polyploidy cells. These results demonstrated thatshd1is involved in cell cycle progression, in particular centrosome duplication and a spindle assembly checkpoint function.

scholarly journals Targeting the Anaphase Promoting Complex/Cyclosome (APC/C) in Multiple Myeloma

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2097-2097
Author(s):  
Susanne Lub ◽  
Anke Maes ◽  
Ken Maes ◽  
Kim De Veirman ◽  
Xavier Leleu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Bone Marrow ◽  
Cell Cycle Progression ◽  
Spindle Assembly Checkpoint ◽  
Plasma Cells ◽  
Spindle Assembly ◽  
Myeloma Cell ◽  
Anaphase Promoting Complex ◽  
Bone Marrow Plasma ◽  
Rpmi 8226

Abstract The discovery of novel agents such as the proteasome inhibitor bortezomib has significantly increased the survival of multiple myeloma (MM) patients. However MM remains an incurable disease mainly due to relapse, associated with significant resistance to therapy including bortezomib. Therefore further investigation to elucidate the disease and the mechanisms leading to drug resistance is necessary. The success of bortezomib highlights the importance of the ubiquitin-proteasomal system (UPS) in MM. The UPS regulates protein turnover and plays a key role is several cellular processes such as apoptosis, cell cycle progression, cell proliferation and DNA replication. The Anaphase Promoting Complex/Cyclosome (APC/C) is an E3 ubiquitin ligase protein complex involved in controlling cell cycle progression. The regulation of APC/C is dependent on 2 co-activators: Cdc20 and Cdh1. The APCCdc20 complex is controlling the metaphase to anaphase transition in mitosis, while APCCdh1 controls mitotic exit and early G1 phase. During metaphase, the activity of APCCdc20 is inhibited by the spindle assembly checkpoint. When all kinetochores are properly attached, the spindle assembly checkpoint is silenced and APCCdc20 becomes activated. When APCCdc20is active, cell cycle proteins are targeted for degradation by the proteasome such as securin and cyclin A and B leading to mitotic exit. Recent studies described that spindle assembly checkpoint is defective in MM cells and that patient samples after chemotherapy and at relapse displayed an increased chromosomal instability signature including Cdc20. The aim of our study is to elucidate the importance and therapeutic potential of APC/C and its co-activators Cdc20 and Cdh1 in MM. Analysis of gene expression in the data of Zhan et al. (Blood 108, 2020-8, 2006) revealed that the co-activator Cdc20 was higher expressed in certain MM sub-groups (PR, MS, CD1, MF) compared to healthy bone marrow plasma cells. Moreover, high Cdc20 expression is correlated with poor prognosis. Cdh1 on the other hand was significantly lower expressed in all MM sub-groups compared to healthy bone marrow plasma cells. Interestingly, lower Cdh1 expression is correlated with poor prognosis. Next, we analyzed whether blocking APC/C would affect MM cells. For this study the pro-drug of TAME (tosyl-L-arginine methyl ester) that has been described as an inhibitor of the APC/C, was used. When the human myeloma cell lines LP-1 and RPMI-8226 were treated with proTAME, an accumulation of the APCCdc20 substrate cyclin B1 was seen already after 6 hours. However the levels of Skp2, an APCCdh1 substrate, were not affected by proTAME treatment. This suggests that proTAME inhibits the APCCdc20 complex but not the APCCdh1complex. We morphologically assessed the effect on number of metaphases on May-Grünwald Giemsa stained cytospins. ProTAME clearly induced an accumulation of LP-1 and RPMI-8226 cells in metaphase. Since a metaphase arrest can lead to cell death, we investigated the effect of proTAME on the viability and apoptosis. A significant dose-dependent decrease in viability and increase in apoptosis was observed after treatment with proTAME of human myeloma cell lines and primary MM cells purified from human and 5T33MM diseased mice. In contrast, other cells from the bone marrow microenvironment were not affected upon proTAME treatment. The induction of apoptosis was accompanied with caspase 3, 8, 9 and PARP cleavage. Western Blot analysis also showed phosphorylation of H2AX suggesting DNA damage upon proTAME treatment. Previous studies showed that MM is a heterogeneous disease consisting of a bulk CD138+ population and a minor CD138- population which is less sensitivity to drugs such as bortezomib. Interestingly, treatment of CD138+/- 5T33MM cells with proTAME demonstrated an equal targeting of both populations. From these results we can conclude that overexpression of Cdc20 by MM cells is correlated with a bad prognosis. Inhibition of APCCdc20 results in a metaphase arrest in MM cells which is associated with reduced viability and induction of apoptosis. Moreover, APC/C inhibition equally targets CD138+ and the more resistant CD138- 5T33MM cells. This study suggests that APC/C and its co-activator Cdc20 could be a new and promising target in MM. Disclosures No relevant conflicts of interest to declare.

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