Cyclical Interactions between Two Outer Doublet Microtubules
in Split Flagellar Axonemes
Susumu Aoyama 1 and Ritsu Kamiya 1*
1 University of Tokyo
* To whom correspondence should be addressed. E-mail: kamiyar{at}biol.s.u-tokyo.ac.jp.
Submitted on June 2, 2005
Revised on July 6, 2005
Accepted on 3 August 2005
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Abstract |
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The beating of cilia and flagella is based on the localized sliding between adjacent outer doublet microtubules; however, the mechanism that produces oscillatory bending is unclear. To elucidate this mechanism, we examined the behavior of frayed axonemes of Chlamydomonas by using high-speed video recording. A pair of doublet microtubules frequently displayed association and dissociation cycles in the presence of ATP. In many instances, the dissociation of two microtubules was not accompanied by noticeable bending, suggesting that the dynein-microtubule interaction is not necessarily regulated by the microtubule curvature. On rare occasions, association and dissociation occurred simultaneously in the same interacting pair, resulting in a tip-directed movement of a stretch of gap between the pair. Based on these observations, we propose a model for cyclical bend propagation in the axoneme.
Key Words:
Chlamydomonas, bending, cilia, dynein, flagella, oscillation
