Team:Paris Saclay/Notebook/July/8

Friday 8th July

Bringing DNA closer

Migration of SP, SP1, SP2, NM, ST1, TD

Visualization

Colony screening PCR on bacteria transformed with pPS16_004 and pPS16_007

By Alice

After transformations, only white bacteria were selected (blue/white screen). They are expected to have plasmids with inserts of interest. PCR with DreamTaq DNA Polymerase is performed following this protocol. Clones selected for PCR are kept on LB+Amp+XGal(2µLXGal/1000µLH2O)+IPTG(2µLIPTG/1000µLH2O). Two primers (1151_pheoR and 1152_pheoF) upstream and downstream the insertion site are chosen. Annealing temperature was 53°C. After amplification, 5 µL of each PCR products and 10 µL of DNA ladder were put on gel and migrated at 100v during 30 min.

PCR products expected were :

Plasmids expected band size (bp)
pPS16_004 865
pPS16_007 763
pPS16_004 (2.2) and pPS16_007 (4.1) Migration

No PCR products are observed, due to an error in the protocol : MilliQ water was used instead of MilliQ and steril water allowing the reduction of RNAse. The same PCR will be performed on July 11.

Electrophoresis of the screening PCR products

By Caroline

Amplification products from the 07/07/2016 screening PCR were put in a 0.8% agarose gel containing BET. The products in solution were mixed with purple loading dye and migrated for 30min. Some clones showed PCR products with lengths close to those expected.

High fidelity PCR

By Caroline

The clones (from 05/07/2016) found with a rightful product lengths were used in another PCR this time with a high fidelity enzyme: Q5. We used a high fidelity enzyme to reduce the error ratio and send to sequencing the PCR products. A PCR was carried out using Q5® High-Fidelity 2X Master Mix and following the usual protocol with pUC19 primers 1151_pheoR and 1152_pheoF.

Plasmids Number of clones tested Expected band size (bp)
pPS16_001 2 998
pPS16_002 3 998
pPS16_003 2 1061
pPS16_005 2 998
pPS16_006 3 998
pPS16_007 1 746
pPS16_001 (1.1), pPS16_002 (1.2) and pPS16_003 (2.1) Migration
pPS16_001, pPS16_003, pPS16_005 and pPS16_006 Migration
pPS16_004 (2.2) and pPS16_007 (4.1) Migration