Analysis of the movement of Chlamydomonas flagella:" the function of the radial-spoke system is revealed by comparison of wild-type and mutant flagella.
Analysis of the movement of Chlamydomonas flagella:" the function of the radial-spoke system is revealed by comparison of wild-type and mutant flagella.
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DOI：
10.1083/jcb.92.3.722
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发表时间：
1982-03
期刊：
影响因子：
--
通讯作者：
Huang B
中科院分区：
文献类型：
--
作者：
Brokaw CJ;Luck DJ;Huang B
突变uni-1产生单毛衣藻细胞，这些细胞在显微镜视野中围绕一个固定点旋转，因此可以很容易地拍摄到鞭毛弯曲的图案。这使我们能够对野生型鞭毛弯曲模式和几个突变菌株的鞭毛弯曲模式进行详细的分析。含有uni-1的细胞，以及含有抑制突变的uni-1重组体supf -1和supf -3，在衣藻中显示出典型的与向前游动相关的不对称弯曲模式，尽管supf -1鞭毛的β频率大约是正常的一半，显然是由于外部动力蛋白臂功能缺陷的结果。pf-17突变已被证明产生不运动的鞭毛，其中径向辐条头和五种典型的轴突多肽缺失。含有pf-17和suppf-2或suppf-3的重组体具有可运动的鞭毛，但仍然缺乏辐状头和相关的多肽。这些缺乏辐状头的重组体的鞭毛弯曲模式是一种几乎对称的、大振幅的模式，这与野生型的模式完全不同。然而，由于所有这些过程在supplff -17重组中都是活跃的，因此将主动滑动转化为弯曲并不需要完整的径向辐条系统，也不需要弯曲产生和弯曲传播。径向辐条系统的功能似乎是通过抑制弯曲循环恢复阶段的反向弯曲的发展，将这些重组体所显示的对称弯曲模式转化为有效游泳所需的非对称弯曲模式。
The mutation uni-1 gives rise to uniflagellate Chlamydomonas cells which rotate around a fixed point in the microscope field, so that the flagellar bending pattern can be photographed easily. This has allowed us to make a detailed analysis of the wild-type flagellar bending pattern and the bending patterns of flagella on several mutant strains. Cells containing uni-1, and recombinants of uni-1 with the suppressor mutations, suppf-1 and suppf-3, show the typical asymmetric bending pattern associated with forward swimming in Chlamydomonas, although suppf-1 flagella have about one-half the normal beta frequency, apparently as the result of defective function of the outer dynein arms. The pf-17 mutation has been shown to produce nonmotile flagella in which radial spoke heads and five characteristic axonemal polypeptides are missing. Recombinants containing pf-17 and either suppf-2 or suppf-3 have motile flagella, but still lack radial-spoke heads and the associated polypeptides. The flagellar bending pattern of these recombinants lacking radial-spoke heads is a nearly symmetric, large amplitude pattern which is quite unlike the wild-type pattern. However, the presence of an intact radial-spoke system is not required to convert active sliding into bending and is not required for bend initiation and bend propagation, since all of these processes are active in suppfpf-17 recombinants. The function of the radial-spoke system appears to be to convert the symmetric bending pattern displayed by these recombinants into the asymmetric bending pattern required for efficient swimming, by inhibiting the development of reverse bends during the recovery phase of the bending cycle.