Branching microtubule nucleation in Xenopus egg extracts mediated by augmin and TPX2.

TitleBranching microtubule nucleation in Xenopus egg extracts mediated by augmin and TPX2.
Publication TypeJournal Article
Year of Publication2013
AuthorsPetry, S, Groen, AC, Ishihara, K, Mitchison, TJ, Vale, RD
JournalCell
Volume152
Issue4
Pagination768-77
Date Published2013 Feb 14
ISSN1097-4172
KeywordsAnimals, Cell Cycle Proteins, Meiosis, Microscopy, Microtubule-Associated Proteins, Microtubules, Nuclear Proteins, Ovum, Phosphoproteins, Xenopus laevis, Xenopus Proteins
Abstract

<p>The microtubules that comprise mitotic spindles in animal cells are nucleated at centrosomes and by spindle assembly factors that are activated in the vicinity of chromatin. Indirect evidence has suggested that microtubules also might be nucleated from pre-existing microtubules throughout the spindle, but this process has not been observed directly. Here, we demonstrate microtubule nucleation from the sides of existing microtubules in meiotic Xenopus egg extracts. Daughter microtubules grow at a low branch angle and with the same polarity as mother filaments. Branching microtubule nucleation requires γ-tubulin and augmin and is stimulated by factors previously implicated in chromatin-stimulated nucleation, guanosine triphosphate(GTP)-bound Ran and its effector, TPX2. Because of the rapid amplification of microtubule numbers and the preservation of microtubule polarity, microtubule-dependent microtubule nucleation is well suited for spindle assembly and maintenance.</p>

DOI10.1016/j.cell.2012.12.044
Alternate JournalCell
PubMed ID23415226
PubMed Central IDPMC3680348
Grant ListGM38499 / GM / NIGMS NIH HHS / United States
GM39565 / GM / NIGMS NIH HHS / United States
K99 GM100013 / GM / NIGMS NIH HHS / United States
R01 GM039565 / GM / NIGMS NIH HHS / United States
R37 GM038499 / GM / NIGMS NIH HHS / United States
/ / Howard Hughes Medical Institute / United States
/ / Howard Hughes Medical Institute / United States