Diameter oscillation of axonemes in sea-urchin sperm flagella.
The 9 + 2 configuration of axonemes is one of the most conserved structures of eukaryotic organelles. Evidence so far has confirmed that bending of cilia and flagella is the result of active sliding of microtubules induced by dynein arms. If the conformational change of dynein motors, which would be a key step of force generation, is occurring in a three-dimensional manner, we can easily expect that the microtubule sliding should contain some transverse component, i.e., a motion in a direction at a right angle to the longitudinal axis of axonemes. Using a modified technique of atomic force microscopy, we found such transverse motion is actually occurring in an oscillatory manner when the axonemes of sea-urchin sperm flagella were adhered onto glass substrates. The motion was adenosine triphosphate-dependent and the observed frequency of oscillation was similar to that of oscillatory sliding of microtubules that had been shown to reflect the physiological activity of dynein arms (S. Kamimura and R. Kamiya. 1989. Nature: 340:476-478; 1992. J. Cell Biol. 116:1443-1454). Maximal amplitude of the diameter oscillation was around 10 nm, which was within a range of morphological change observed with electron microscopy (F. D. Warner. 1978. J. Cell Biol. 77:R19-R26; N. C. Zanetti, D. R. Mitchell, and F. D. Warner. 1979. J. Cell Biol. 80:573-588).
Sakakibara
Hajime M
HM
Department of Life Sciences, Graduate School of Arts and Sciences, the University of Tokyo, Komaba, Meguro, Tokyo, Japan.
Kunioka
Yuki
Y
Yamada
Takenori
T
Kamimura
Shinji
S
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D008297:Male; D018625:Microscopy, Atomic Force / Q000379:methods; D020409:Molecular Motor Proteins / Q000502:physiology*; D012617:Sea Urchins / Q000502:physiology*; D013081:Sperm Motility / Q000502:physiology*; D013082:Sperm Tail / Q000502:physiology* / Q000648:ultrastructure
D020409:Molecular Motor Proteins; D000255:Adenosine Triphosphate