Segmented and polarity-marked microtubules are very useful for many different types of in vitro assays.
Segmented microtubules are microtubules with a bright seed and dim elongated segments on both ends.
Selective elongation of one end is achieved by inclusion of NEM-treated tubulin, a competitive inhibitor of minus end polymerization. Also, segmented and polarity marked microtubules can be made from different color tubulins instead of different intensity of a single color tubulin as described here. Note that the precise ratios of labeled to unlabeled tubulin described here may need to be adjusted depending on the labeled tubulin prep. Segmented Taxol Microtubules 1. Therefore, only add the seeds after the elongation mix has warmed up.