TAILPCRProtocol

TAIL is a series of reactions that are intended to map where a T-DNA (transfer DNA) has inserted within the genome. The main components of the 3 reactions are the AD (Arbitrary Degenerate) primers, border primers, and DNA from the T-DNA lines that are to be mapped. AD primers are degenerate primers that anneal throughout the genome. The border primers are specific for the left and right borders of the T-DNA. From the primary reaction to the tertiary, the border primers get closer to the edge of the T-DNA. That is why a ''shift'' is visible when running a gel with the secondary and tertiary reactions next to each other. The success rate of TAIL-PCR varies, depending onhow many DNA samples, AD primers, and border primers are used. 

1. Dilute the DNA sample 1:5 (Dilute more or less depending on DNA concentration.) 

2. Add 5μL DNA, and 5μL AD primers to PCR plate according to the diagram below (each AD primer has a specific concentration, see Additional Information at the end of the protocol):
NOTE: Keep plate on ice throughout the procedure. 

Key:
DNA1, DNA2, DNA3, ... = Individual DNA samples for T-DNA mapping. Add 5μL DNA (1° reaction) in an entire horizontal row (e.g. A) for each individual. 
AD1, AD2, AD3, ... = Arbitrary Degenerate primers. Add 5μ of the 4X AD primer (1° reaction) to each vertical column as diagram indicates. 

lightyellow= Left half of plate-Add LB1 primer cocktail. 

grey=Right half of plates-Add RB1 primer cocktail. 



3. Start the 1° Reaction (detailed in Additional Information) program on thermal cycler and press PAUSE, letting the block cool to 4°C. 

4. Mix the LB1 and RB1 cocktails according to TAIL Recipe spreadsheet included. 
NOTE: Add Taq polymerase last. 

5. Add 10μL of each cocktail (LB1 and RB1) to appropriate wells according to previous diagram. 

6. Place plate in thermal cycler and press PAUSE, again to allow the reaction to proceed. 

7. To prepare the 2° reaction, dilute 1° TAIL reaction 200-fold by transferring 1μL PCR products to 199μL ddH2O. (This is most easily achieved through the use of a multi-channel pipette.) 

8. Set up 2° reaction plate according to same diagram, except use 4μL diluted DNA. NOTE: As before, keep plate on icethroughout preparation. 

9. Add 5μL of the AD primers to the appropriate wells. 

10. Start 2°ree; reaction program on thermal cycler and press PAUSE. 

11. Add 11μL of border (LB2 or RB2) cocktail to appropriate wells and place plate in thermal cycler. Press PAUSE to allow reaction to proceed. 

12. Once the 2° reaction has completed, the products can either be sequenced or a 3° reaction can be run to further purify the PCR products if there are many nonspecific products. CONTINUE if a 3° reaction is needed. To prepare samples for sequencing, SKIP to step 25. 

13. The 3° reaction is prepared like the 2° needs to be diluted 100-fold and the overall reaction volume is 50μL. Add the diluted products from the 2° reaction to a new PCR plate. Again, keep reaction on ice and use a multi-channel pipette for diluting. 

14. Add 12.5μL of the AD primers to the appropriate wells. 

15. Start the 3° reaction program on the thermal cycler and press PAUSE. 

16. Mix the LB3 and RB3 cocktail (adding the Taq last) and add 32.5μL to appropriate half of plate. 

17. Flash spin in a table top centrifuge to assure all reaction contents are at the bottom of the wells. 

18. Place plate in thermal cycler and press PAUSE again to allow reaction to proceed. 

19. To sequence entire contents of plate, SKIP to step 25. To run a gel and visualize the 3°ree; reactions, gollow these steps: Prepare a large 1% agarose gel with 4 rows of 50 wells (200 total wells). 

20. Add the appropriate ladder (100bp or 1kb) to the first and last well in each row. 

21. Using a multi-channel pipette, draw 7μL from row A or the 2° reaction. Expel this amount on a piece of parafilm. Using the same pipette tips, draw 3μL of loading dye and add it to the droplets on the parafilm. Mix the dye and reaction contents by pipetting up and down. 

22. Without changing tips, draw all 10μL of the samples and add them to the gel starting next to the ladder in the top, left portion of the gel. NOTE: Using the multi-channel pipette will leave a space between the samples, this isdesired. 

23. Discard the pipette tips and repeat previous step until entire 2° reaction contents are loaded into the gel. Assure a space is left between all 2° reactions added to gel. 

24. Now, do the same with the 3° reactions, add the 10μL of the 3° reactions directly next to the 2° reactions. If loaded properly, all lanes will be filled without spaces. This will make the gel easier to analyze. There should be a visible shift in product length from the 2° to the 3° raction. If there are multiple bands visible in one lane, purify individual bands for sequencing via the Topo Cloning Procedure. If single bands exist in the 3° reaction, continue to step 25 for product purification. 

25. The PCR products must be purified before they can be squenced. This can be done individually via the Qiagen PCR purification protocol or enzyme purified as explained in this protocol. Transfer 5μ: of 2° reaction PCR products to a new plate. (Again, this is very easy with a multi-channel pipette). 

26. Mix the Enzyme (Exol/SAP) Purification cocktail as follows: 

27. Add 2.0μL enzyme purification cocktail to DNA samples (on ice). Flash spin plate in a tabletop centrifuge. 

28. Run reaction in thermal cycler. Use following program: 
    Step 1= 37°C for 20 min. 
    Step 2= 80°C for 15 min. 
    Step 3= 4°C forever 
    Step 4= END 

**The reactions are now ready to be sequenced with the corresponding border primers. 

ADDITIONAL INFORMATION 

TAIL 1° REACTION PROGRAM:

Control Method: CALCULATED