A model for cleavage plane determination in early amphibian and fish embryos

Martin Wühr, Edwin S. Tan, Sandra K. Parker, H. William Detrich, Timothy J. Mitchison

Research output: Contribution to journalArticlepeer-review

117 Scopus citations

Abstract

Current models for cleavage plane determination propose that metaphase spindles are positioned and oriented by interactions of their astral microtubules with the cellular cortex, followed by cleavage in the plane of the metaphase plate [1, 2]. We show that in early frog and fish embryos, where cells are unusually large, astral microtubules in metaphase are too short to position and orient the spindle. Rather, the preceding interphase aster centers and orients a pair of centrosomes prior to nuclear envelope breakdown, and the spindle assembles between these prepositioned centrosomes. Interphase asters center and orient centrosomes with dynein-mediated pulling forces. These forces act before astral microtubules contact the cortex; thus, dynein must pull from sites in the cytoplasm, not the cell cortex as is usually proposed for smaller cells. Aster shape is determined by interactions of the expanding periphery with the cell cortex or with an interaction zone that forms between sister-asters in telophase. We propose a model to explain cleavage plane geometry in which the length of astral microtubules is limited by interaction with these boundaries, causing length asymmetries. Dynein anchored in the cytoplasm then generates length-dependent pulling forces, which move and orient centrosomes.

Original languageEnglish (US)
Pages (from-to)2040-2045
Number of pages6
JournalCurrent Biology
Volume20
Issue number22
DOIs
StatePublished - Nov 23 2010

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Fingerprint Dive into the research topics of 'A model for cleavage plane determination in early amphibian and fish embryos'. Together they form a unique fingerprint.

Cite this