Figure 3
Microtubule dynamics revealed by photoconverting expressed Dendra2-α-tubulin. A distal portion of a Dendra2-α-tubulin expressing HeLa cell was photoconverted within 5 sec (entire field shown in the panels). Note, that photoconversion was only incomplete, as indicated by the relatively strong remaining green fluorescence (visible in the left panel of row 2). Within 3-7 minutes, red photoconverted and remaining green α-tubulin pools intermixed (arrows), consistent with the known dynamic continuous polimerization and depolimerization of microtubules, and the diffusional mobility of unassembled α/β-tubulin subunit-dimers in the cytoplasm.