Effect of microvilli on lateral diffusion measurements made by the fluorescence photobleaching recovery technique

To consider the effect of surface microvilli on measurements of lateral diffusion by fluorescence photobleaching recovery, we have measured the diffusion of the lipid probe 3,3'-dihexadecyl indocarbocyanine iodide on the villated main body and unvillated budding polar body of unfertilized mouse eggs. On the main body we found D = (6.41 +/- 0.62) x 10(-9) cm(2)/s with (77.0 +/- 2.1)% recovery, and on the budding polar body we found D = (7.05 +/- 0.75) x 10(-9) cm(2)/s with (84.7 +/- 1.3)% recovery. We thus find only slight differences in diffusion in the two regions.