User:Kalkao/notebook/Transfection of T7 DNA
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This protocol was developed from the supplementary information of the "Refactoring bacteriophage T7" paper.
- Place all of the pipette tip boxes in the -20*C fridge to cool before use.
- Place a test tube in the heat block for each transfection sample.
- Place T-broth agar plates in the 37*C incubation room to warm up the plates- one for each sample.
- Refill the ice bucket with the IJ1126 cell suspension to keep the cells cold.
- Obtain the phage DNA stock, and note the concentration.
- The optimal amount of DNA to use is 1e9 to 4e9 molecules for the conditions used in the Preparing Competent Cells for Phage Transfection protocol.
- You will need to calculate the volume of DNA stock needed to provide this amount.
- Setup a 1.7mL centrifuge tube for each sample. Use an additional tube to hold MilliQ water for the blank/control samples.
- Pipette 200uL of the IJ1126 culture into each tube.
- Use the chilled pipette tips.
- Work quickly because it is very important to keep the culture suspension cold in this step.
- Add the assigned amount of DNA to each centrifuge tube.
- use the chilled pipette tips.
- Be careful not to touch the lip of the DNA stock because it is easily contaminated
- Be careful not to get ice on the inside of the centrifuge tube lid because the ice may fall into the tube.
- Always add DNA to the centrifuge tubes in numerical order to avoid confusion.
- Spin down the tube quickly before adding the DNA so the culture is at the bottom of the tube and will not leave the tube when it is opened.
- Allow the DNA/IJ1126 mixture to incubate on ice for 30 minutes.
- During the 30 minute incubation, prepare a tube of warm soft agar for each sample:
- Obtain soft agar from the 55*C incubator.
- Microwave the bottle of the soft agar for 50 seconds at 50% power.
- Place paper towels under the bottle and use paper towels when handling the bottle because the soft agar may boil.
- Pipette 3mL of soft agar into each of the small test tubes on the heat block (~42-45*C).
- Pay special attention to sterile technique.
- Obtain the T-broth agar plates from the 37*C incubation room- they should be warmed up.
- Label one plate for each tube/sample with the number corresponding to the tube.
- After the 30 minute incubation, heat shock each sample one by one:
- Spin down the tube briefly using the mini centrifuge.
- Use the 1000uL micropipette to suck up the whole mixture out of the tube.
- Eject the mixture into a hot soft agar test tube.
- Pay special attention to sterile technique.
- Tap the test tube on the lab bench lightly to mix for 5-15 seconds.
- Pour the test tube onto its corresponding plate.
- Allow the soft agar to solidify.
- When the soft agar layer has solidified, place the plates in the 37*C incubation room to incubate for 3-5 hours.
- After the 3-5 hour incubation, retrieve the plates and count the plaques.
- To stop the plaques from growing and to keep the plates, place them in the 4*C fridge.