Lidstrom:Colony PCR

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Revision as of 21:06, 6 March 2012 by Janet B. Matsen (Talk | contribs)
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General:

  • Use Taq. It is cheap. Do not use Phusion. It is ~$1/50uL rxn. Taq is less accurate & less fast but that's fine.
  • The thermocycling denaturation & extension temperature should be that recommended by your particular PCR kit. I have seen 68oC & 72oC.
  • The primer concentration varies in different people's recipes. Janet hasn't tested variations.
  • One fatal flaw: overloading the PCR. Just a tiny piece of a colony should be used.
  • If they aren't working, you can put them in tubes, put them at 95oC for a while, then centrifuge they lysed cells so all the debris falls out. Run PCR from on the aqueous portion.

Parameters:

  • T_anneal: up to you. For VF2 & VR 54-56oC works well.
  • t_anneal: use 30s/kb and round up.
  • rxn volume: 10-25 uL. Too small of a volume can result in overloading without noticing.


Comments

  • It might be tempting to make a 1X soltuion with primers included, store it in the freezer, and thaw it as you need to use it. The problem with this: primer dimers may amplify. Obviously the degree to which this is an issue will depend on your primers, but it is likely worth avoiding by sticking with the 2X freezer stock. Also, there may be issues with the protein's stability upon freezing in a lower buffer/stabilizer concentration.
  • Stay tuned for an image of what "overloading" can look like!
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