Platelets from Mx1-C1 mice exhibit an abnormal microtubule ultrastructure. (A) Electron micrographs of portions of individual WT and Mx1-C1 platelets. Scale bars, 100 nm. (B) Quantification of the number of microtubule coils. Data were obtained from 8 WT and Mx1-C1 platelets each and presented as means ± SEM. *P < .01. (C) Western blot analysis of platelet extract with anti–α-tubulin and anti–β-tubulin Abs.