Analysis of Mitotic Checkpoint Function in Xenopus Egg Extracts

2018 ◽  
Vol 2018 (9) ◽  
pp. pdb.prot099853 ◽  
Author(s):  
Yinghui Mao
Keyword(s):  
Mitotic Checkpoint ◽  
Egg Extracts ◽  
Xenopus Egg ◽  
Xenopus Egg Extracts

scholarly journals ZW10 links mitotic checkpoint signaling to the structural kinetochore

2005 ◽  
Vol 169 (1) ◽  
pp. 49-60 ◽  
Author(s):  
Geert J.P.L. Kops ◽  
Yumi Kim ◽  
Beth A.A. Weaver ◽  
Yinghui Mao ◽  
Ian McLeod ◽  
...  
Keyword(s):  
Chromosome Instability ◽  
Mitotic Checkpoint ◽  
Human Cells ◽  
Structural Elements ◽  
Checkpoint Signaling ◽  
Daughter Cells ◽  
Primary Mechanism ◽  
Egg Extracts ◽  
Xenopus Egg ◽  
Xenopus Egg Extracts

The mitotic checkpoint ensures that chromosomes are divided equally between daughter cells and is a primary mechanism preventing the chromosome instability often seen in aneuploid human tumors. ZW10 and Rod play an essential role in this checkpoint. We show that in mitotic human cells ZW10 resides in a complex with Rod and Zwilch, whereas another ZW10 partner, Zwint-1, is part of a separate complex of structural kinetochore components including Mis12 and Ndc80–Hec1. Zwint-1 is critical for recruiting ZW10 to unattached kinetochores. Depletion from human cells or Xenopus egg extracts is used to demonstrate that the ZW10 complex is essential for stable binding of a Mad1–Mad2 complex to unattached kinetochores. Thus, ZW10 functions as a linker between the core structural elements of the outer kinetochore and components that catalyze generation of the mitotic checkpoint-derived “stop anaphase” inhibitor.

scholarly journals The bulk of unpolymerized actin in Xenopus egg extracts is ATP-bound.

1995 ◽  
Vol 6 (2) ◽  
pp. 227-236 ◽  
Author(s):  
J Rosenblatt ◽  
P Peluso ◽  
T J Mitchison
Keyword(s):  
Actin Polymerization ◽  
Critical Concentration ◽  
Large Fraction ◽  
Nucleotide Exchange ◽  
Chromatography Analysis ◽  
Thymosin Beta 4 ◽  
Egg Extracts ◽  
Xenopus Egg ◽  
Xenopus Egg Extracts

Non-muscle cells contain 15-500 microM actin, a large fraction of which is unpolymerized. Thus, the concentration of unpolymerized actin is well above the critical concentration for polymerization in vitro (0.2 microM). This fraction of actin could be prevented from polymerization by being ADP bound (therefore less favored to polymerize) or by being ATP bound and sequestered by a protein such as thymosin beta 4, or both. We isolated the unpolymerized actin from Xenopus egg extracts using immobilized DNase 1 and assayed the bound nucleotide. High-pressure liquid chromatography analysis showed that the bulk of soluble actin is ATP bound. Analysis of actin-bound nucleotide exchange rates suggested the existence of two pools of unpolymerized actin, one of which exchanges nucleotide relatively rapidly and another that apparently does not exchange. Native gel electrophoresis of Xenopus egg extracts demonstrated that most of the soluble actin exists in complexes with other proteins, one of which might be thymosin beta 4. These results are consistent with actin polymerization being controlled by the sequestration and release of ATP-bound actin, and argue against nucleotide exchange playing a major role in regulating actin polymerization.

scholarly journals The Prereplication Complex Recruits XEco2 to Chromatin to Promote Cohesin Acetylation in Xenopus Egg Extracts

2012 ◽  
Vol 22 (11) ◽  
pp. 977-988 ◽  
Author(s):  
Torahiko L. Higashi ◽  
Megumi Ikeda ◽  
Hiroshi Tanaka ◽  
Takuro Nakagawa ◽  
Masashige Bando ◽  
...  
Keyword(s):  
Egg Extracts ◽  
Xenopus Egg ◽  
Xenopus Egg Extracts

scholarly journals Multiple mechanisms determine ER network morphology during the cell cycle in Xenopus egg extracts

2013 ◽  
Vol 203 (5) ◽  
pp. 801-814 ◽  
Author(s):  
Songyu Wang ◽  
Fabian B. Romano ◽  
Christine M. Field ◽  
Tim J. Mitchison ◽  
Tom A. Rapoport
Keyword(s):  
Cell Cycle ◽  
Adaptor Protein ◽  
Sensitive Factor ◽  
Protein Receptors ◽  
Egg Extracts ◽  
Organizing Center ◽  
Xenopus Egg ◽  
Guanosine Triphosphatase ◽  
Xenopus Egg Extracts ◽  
Network Morphology

In metazoans the endoplasmic reticulum (ER) changes during the cell cycle, with the nuclear envelope (NE) disassembling and reassembling during mitosis and the peripheral ER undergoing extensive remodeling. Here we address how ER morphology is generated during the cell cycle using crude and fractionated Xenopus laevis egg extracts. We show that in interphase the ER is concentrated at the microtubule (MT)-organizing center by dynein and is spread by outward extension of ER tubules through their association with plus ends of growing MTs. Fusion of membranes into an ER network is dependent on the guanosine triphosphatase atlastin (ATL). NE assembly requires fusion by both ATL and ER-soluble N-ethyl-maleimide–sensitive factor adaptor protein receptors. In mitotic extracts, the ER converts into a network of sheets connected by ER tubules and loses most of its interactions with MTs. Together, these results indicate that fusion of ER membranes by ATL and interaction of ER with growing MT ends and dynein cooperate to generate distinct ER morphologies during the cell cycle.

scholarly journals The nuclear envelope prevents reinitiation of replication by regulating the binding of MCM3 to chromatin in Xenopus egg extracts

1995 ◽  
Vol 5 (11) ◽  
pp. 1270-1279 ◽  
Author(s):  
Mark A. Madine ◽  
Chong-Yee Khoo ◽  
Anthony D. Mills ◽  
Christine Musahl ◽  
Ronald A. Laskey
Keyword(s):  
Nuclear Envelope ◽  
Egg Extracts ◽  
Xenopus Egg ◽  
Xenopus Egg Extracts
Sign in / Sign up

Export Citation Format

Share Document