Format

Send to

Choose Destination
Cell. 1994 Nov 4;79(3):475-86.

A MAP kinase-dependent spindle assembly checkpoint in Xenopus egg extracts.

Author information

1
Department of Physiology, University of California, San Francisco 94143-0444.

Abstract

Like early Xenopus embryos, extracts made from Xenopus eggs lack the cell cycle checkpoint that keeps anaphase from occurring before spindle assembly is complete. At very high densities of sperm nuclei, however, microtubule depolymerization arrests the extracts in mitosis. The arrested extracts have high levels of maturation-promoting factor activity, fail to degrade cyclin B, and contain activated ERK2/mitogen-activated protein (MAP) kinase. The addition of the purified MAP kinase-specific phosphatase MKP-1 demonstrates that MAP kinase activity is required for both the establishment and maintenance of the mitotic arrest induced by spindle depolymerization. Increased calcium concentrations, which release unfertilized frog eggs from their natural arrest in metaphase of meiosis II, have no effect on the mitotic arrest.

PMID:
7954813
DOI:
10.1016/0092-8674(94)90256-9
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center