Figure 4.

Central apparatus orientation, high calcium buffer. (A) Examples of data obtained from axonemes isolated from four strains after microtubule sliding in pCa4 buffer. The lines drawn from the center of each cross section delineate the active and inactive areas defined in Fig. 1B. The dots represent the orientation of the C1 microtubule for individual transverse sections. Particularly striking examples of the C1 microtubule oriented toward the position of microtubule sliding are indicated by arrows. To view all data, see Fig. 6. (B) Percentage of transverse sections in which the C1 microtubule was oriented toward the active area as shown in A. Light bars indicate the expected percentage of events. The difference between the expected and observed values is darkly shaded. Strains in which this difference is significant are indicated by asterisks (χ² test; P < 0.01). The total number of transverse sections included is indicated below each mutant.