Self-Organization of MTOCs Replaces Centrosome Function during Acentrosomal Spindle Assembly in Live Mouse Oocytes
2007 | journal article; research paper. A publication with affiliation to the University of Göttingen.
Jump to: Cite & Linked | Documents & Media | Details | Version history
Documents & Media
Details
- Authors
- Schuh, Melina ; Ellenberg, Jan
- Abstract
- Chromosome segregation in mammalian oocytes is driven by a microtubule spindle lacking centrosomes. Here, we analyze centrosome-independent spindle assembly by quantitative high-resolution confocal imaging in live maturing mouse oocytes. We show that spindle assembly proceeds by the self-organization of over 80 microtubule organizing centers (MTOCs) that form de novo from a cytoplasmic microtubule network in prophase and that functionally replace centrosomes. Initially distributed throughout the ooplasm, MTOCs congress at the center of the oocyte, where they contribute to a massive, Ran-dependent increase of the number of microtubules after nuclear envelope breakdown and to the individualization of clustered chromosomes. Through progressive MTOC clustering and activation of kinesin-5, the multipolar MTOC aggregate self- organizes into a bipolar intermediate, which then elongates and thereby establishes chromosome biorientation. Finally, a stable barrel-shaped acentrosomal metaphase spindle with oscillating chromosomes and astral-like microtubules forms that surprisingly exhibits key properties of a centrosomal spindle.
- Issue Date
- 2007
- Journal
- Cell
- ISSN
- 0092-8674
- Language
- English