UA Biophysics:Protocols:Tubulin Polymerization with AlexaFluor 488 staining
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OBJECTIVE
The objective of this protocol is to artificially polymerize microtubules from tubulin and to stain them for fluorescence microscopy.
MATERIALS
Materials:
- Biotin labeled tubulin
- TAMRA Rhodamine labeled tubulin protein
- Taxol
- GTP [100mM]
- BRB80 buffer
- MgCl2 [50mM]
- DMSO
- AlexaFluor 488
- PBS-BSA 0.1%
- β-mercaptoethanol 14M
- Wet chamber
- Coverslips and slides
- Nail polish
RECIPE
Microtubules were prepared by polymerizing 20 microgram of biotin-labeled tubulin (Cytoskeleton Inc., Denver, CO) in 6.5μl of growth solution containing 4 mM of MgCl2, 1 mM of GTP, and 5% DMSO (v/v) in BRB80 buffer for 30 min at 37 °C. The microtubules were then 100-fold diluted and stabilized in 10 microM paclitaxel [taxol] (Sigma, Saint Louis MO).
- Prepare 1 ml PBS+β-mercaptoethanol 14mM. Put aside.
- Prepare 13.0 μl of growth solution by adding
i. MgCl2 [50mM]: 1.04 μl ii. GTP [25mM]: 2.00 μl iii. DMSO [100%]: 0.65 μl iv. BRB80: 9.40 μl
- From this growth solution extract 6.5 μl and pour 20μg of biotin-labeled tubulin (Cytoskeleton Inc., Denver, CO) in it. Discard the other 6.5μl .
- Prepare 500μl BRB80 + Taxol 10μM.
- Disolve the 6.5 μl of growth solution + biotion-labeled tubulin in the 500μl BRB80 + Taxol 10μM.
- From the 506.5μl take 20μl and deposit it on a thin slide.
- Let dry.
- Rinse with PBS-BSA 0.1% and leave for 30min at room temperature.
- Add 20μl of Alexa 488 2000x in PBS.
- Leave in a humid petri dish at room temperature for 30min.
- Put a droplet of PBS+β-mercaptoethanol (~20μl).
- Immediately put on a thick slide. Then seal with nail polish so PBS+β-mercaptoethanol does not evaporate.
- Let dry. Do not expose to light. Ready to be imaged.