Rapidly thaw frozen tubulin, then immediately place on ice. Unpolymerized tubulin is labile! 200 µL aliquot of tubulin (cycled)--in BRB80, stored in -70℃ 100 µL glycerol 10 µL 0.1 M MgCl2 3 µL 0.1 M GTP (pH adjusted to neutral) or 50 µL aliquot of tubulin (cycled)--in BRB80, stored in -70℃ 25 µL glycerol 2.5 µL 0.1 M MgCl2 0.75 µL 0.1 M GTP (pH adjusted to neutral)
Add other ingredients. Mix gently, but thoroughly. Spin tube briefly.
Aliquot tubulin to small (500 µL) tubes that have been prechilled on ice. A standard titration of binding activity requires ~15 µLs.
Flash freeze aliquots in liquid nitrogen and store at -70℃.
To make polymerized MTs:
Place "seeds" at 37℃ for 30 min.
Add taxol to 10 µM. I add the required amount of taxol in 1 µL (i.e. for a 12 µL aliquot of MT seeds, add 1 µL of 0.13 mM taxol in DMSO). Mix in gently.
Incubate an additional 15 min. at 37℃.
Taxol-stabilized MTs are stable at room temp. for several days. NOTE: To dilute MTs, make a cocktail similar to that which the seeds are in: 200 µL BRB80 100 µL glycerol 10 µL 0.1 M MgCl2 Adjust small aliquots to 10 µM taxol prior to use.
Making Long Microtubules 100 µls Tubulin (3-5 mg/ml) 3.3 µls 100 mM MgCl2 1.3 µls 100 mM GTP 2 µls seeds
45 minutes at 37℃
Add Taxol ~7µls
15 minutes at 37℃
8/25/95 NEW Protocol for Assembling Microtubules •To a tube containing 10µls of 10mg/ml tubulin add: 10µls G-PEM with 30% Glycerol; 0.75 µl of rhodamine labelled tubulin •Place at 35℃ for 10' •remove to room temp. •Immediately add paclitaxel (taxol) to 10µM final (2µls of a 0.1 mM stock taxol into 20µls) •the microtubules formed by this method have a mean length of ~2µm and can be stable for upto several weeks at room temp.