Cloning – Purified OsHV-1 ORF117 PCRs

Purified OsHV-1 ORF117 PCRs from earlier today were separately ligated using the Original TA Cloning Kit (Invitrogen).


Ligation reactions:

  • PCR product: 5μL
  • 5x Buffer: 2μL
  • Vector (pCR2.1): 2μL
  • T4 Ligase: 1μL

Incubate 1hr @ RT.


50μL of X-gal (40mg/mL) was added to a LB-Amp100 plate, spread and warmed @ 37C.

Three vials of OneShot TOP 10 chemically competent cells (Invitrogen) were thawed on ice. 5μL of the ligation reaction was added to the cells, gently mixed and incubated on ice for 5mins. Thecells were transferred to the LB-Amp100+X-gal plates, spread and incubated O/N at 37C.


All three transformations failed. All of them produced only blue colonies and very few total colonies.

The low number of colonies prompted me to look at the troubleshooting in the manual for The Original TA Cloning Kit (Invitrogen). It turns out that after six months of storage, the vector begins to lose the T overhangs. The kit I used is from 2014; three years beyond the tentative expiration date. This is likely the cause of the failed transformations.

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