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.
The PCR products were separately ligated using The Original TA Cloning Kit (Invitrogen).
SINGLE REACTION VOL (μL)
10x Ligase Buffer
T4 DNA Ligase
Ligation reactions were set up on ice.Combined 5μL of purified PCR product with 5μL of ligation master mix in a 1.5mL snap cap tube. Incubated 24hrs @ RT.
50μL of X-gal (20mg/mL) was added to a LB-Amp100 plates, spread and warmed @ 37C.
Five vials of OneShot TOP 10 chemically competent cells (Invitrogen) were thawed on ice. 3μL of the ligation reaction was added to the cells, gently mixed and incubated on ice for 5mins. 50μL of cells were transferred to the LB-Amp100+X-gal plates, spread and incubated O/N at 37C.
Cloned purified PCR products from 20140813 into the pCR2.1 vector using The Original TA Cloning Kit (Life Technologies/Invitrogen), according to the manufacturer’s protocol. Used 2uL of PCR product. Incubated ligation at RT for 15mins. Transformed TOP10 chemically competent cells (Life Technologies/Invitrogen) following the Rapid Transformation protocol (added 4uL of ligation reaction to thawed cells; incubated on ice 5mins; plated 50uL of cells on pre-warmed LB-Amp (50ug/mL) + X-gal (40uL of 40mg/mL stock) plates). Incubated O/N at 37C.
Both cloning reactions look great; lots of potential clones. Will screen nine from each via PCR for detection of our desired insert.