QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

Help viewing high resolution images Return to article

Fig. 1. The regulation of dynein activity in a switching model of beating flagella and the experimental design for testing the hypothesis. (A) In the sea urchin sperm flagellum, principal and reverse bends (P_B and R_B) are cyclically formed in the plane of beat (white), which is perpendicular to the plane of the CP (grey). (B) The formation of P_B and R_B is due to P-sliding (P_S) and R-sliding (R_S), respectively, induced by the dynein arms of the doublets 7 and 3 (or 4) (Nakano et al., 2003). (C) A model, based on our previous study (Morita and Shingyoji, 2004), illustrating the postulated sequential regulation of dynein activity (with time and along the flagellum), which induces oscillation for a half beat cycle (from top to bottom). (D) Interpretation of the previous experiment (Morita and Shingyoji, 2004). Externally applied bending induces backward sliding between the two sets of doublets in the elastase-treated axonemal fragment when ATP was applied locally and transiently by using caged-ATP with a UV flash. The testing hypothesis is that backward sliding is caused by switching of the activity of dynein from doublet 7 to doublet 3 (in the 8-3 pattern). (E) Overview of the present experiments. The effects of the direction of externally applied bending and those of the dynein attachment states on the subsequent regulation of dynein activity are analysed by using three types (1-3) of axonemes obtained from elastase-treated quiescent flagella. Finally, the switching of dynein activity by bending is tested by measuring the velocity of microtubule sliding.

Return to article