• Register
X
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

X

Leaving Community

Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.

No
Yes

The degradation of two mitotic cyclins contributes to the timing of cytokinesis.

BACKGROUND: Cytokinesis occurs just as chromosomes complete segregation and reform nuclei. It has been proposed that cyclin/Cdk kinase inhibits cytokinesis until exit from mitosis; however, the timer of cytokinesis has not been experimentally defined. Whereas expression of a stable version of Drosophila cyclin B blocks cytokinesis along with numerous events of mitotic exit, stable cyclin B3 allows cytokinesis even though it blocks late events of mitotic exit. We examined the interface between mitotic cyclin destruction and the timing of cytokinesis. RESULTS: In embryonic mitosis 14, the cytokinesis furrow appeared 60 s after the metaphase/anaphase transition and closed 90 s later during telophase. In cyclin B or cyclin B3 mutant cells, the cytokinesis furrow appeared at an earlier stage of mitosis. Expression of stable cyclin B3 delayed and prolonged furrow invagination; nonetheless, cytokinesis completed during the extended mitosis. Reduced function of Pebble, a Rho GEF required for cytokinesis, also delayed and slowed furrow invagination, but incomplete furrows were aborted at the time of mitotic exit. In functional and genetic tests, cyclin B and cyclin B3 inhibited Pebble contributions to cytokinesis. CONCLUSIONS: Temporal coordination of mitotic events involves inhibition of cytokinesis by cyclin B and cyclin B3 and punctual relief of the inhibition by destruction of these cyclins. Both cyclins inhibit Pebble-dependent activation of cytokinesis, whereas cyclin B can inhibit cytokinesis by additional modes. Stable cyclin B3 also blocks the later return to interphase that otherwise appears to impose a deadline for the completion of cytokinesis.

Pubmed ID: 12620185

Authors

  • Echard A
  • O'Farrell PH

Journal

Current biology : CB

Publication Data

March 4, 2003

Associated Grants

  • Agency: NIGMS NIH HHS, Id: GM37193
  • Agency: NIGMS NIH HHS, Id: R01 GM037193
  • Agency: NIGMS NIH HHS, Id: R01 GM037193-17
  • Agency: NIGMS NIH HHS, Id: R01 GM037193-18

Mesh Terms

  • Anaphase
  • Animals
  • Cell Division
  • Cyclin B
  • Drosophila
  • Drosophila Proteins
  • Guanine Nucleotide Exchange Factors
  • Mitosis
  • Mutation
  • Wing