TurboBlotting under Alkaline
Conditions: Southern Blot
					Adapted from Chomczynsli, (1992). Analytical
Biochemistry 201: 134-139.
		 
		
  - Run 1 - 5 µg gDNA per lane, photograph
  the gel with a fluorescent ruler.
  
 - Soak gel in 0.25 M HCl for 15 minutes (hydrolyzes
  long molecules into shorter ones for transfer).
  
 - Rinse briefly in water.
  
 - Soak gel in denaturing buffer 2 X 30 min. at
  RT with gentle aggitation.
  
 - Soak gel in transfer buffer for 15 min with gentle
  aggitation. At the same time, wet and soak the Nytran membrane in dH 2
  O.
  
 - Place the bottom half of the TurboBlotting tray
  on a level bench (see diagram on next page).
  
 - Place 20 sheets of dry absorbent paper (or appropriately
  sized paper towels) inside the bottom half of the blotting tray.
  
 - Place 4 sheets of dry blotting paper (or 3MM
  paper) on top of the stack.
  
 - Place one sheet of wet (soaked in transfer buffer)
  blotting paper on top of the stack.
  
 - Place the prewetted Nytran on top of the stack.
  
 - Place the gel on top of the Nytra. Surround the
  gel with parafilm if necessary. Make sure there are no air bubbles between
  the gel and the Nytran.
  
 - Wet the surface of the gel with a small amount
  (about 1 ml) of transfer buffer and place 3 sheets of wet (transfer buffer)
  blotting paper on top of the gel.
  
 - Attach the top half of the buffer tray to the
  bottom half. Add 125 ml of transfer 
  buffer to the tray.
   - Start the transfer by connecting the gel stack
  to the buffer using a wick that has been prewetted in transfer buffer.
  Make sure the entire gel is covered with wick. 
  
 - Place a wick cover on top to prevent evaporation.
  
 - Continue transfer for 1-4 hours.
  
 - After the transfer is complete, remove the Nytran
  and gel as a single unit. Mark the membrane with a VWR lab marker to indicate
  which side has the DNA. Also, cut the gel and membrane along the bottom
  to the wells and notch the top left corner of the Nytran to give it an
  orientation.
  
 - Gently wash the membrane in 100 ml of 1X neutralizing
  buffer for 5 min. (Use 5X stock solution)
  
 - Place the Nytran, DNA side up, on a clean paper
  towel and allow it to air dry for about 5 minutes. Then, cross-link the
  DNA to the Nytran with 2.5 minutes of UV irradiation. The blot is ready
  for prehybridization.
 
		
  
  
Special Notes
  - Do not allow RNA to be transferred O/N; weak
  signal due to hydrolyzed RNA.
  
 - O/N transfer of DNA to Nytran is OK but not to
  nitrocellulose.
  
 - Membranes can be dried for 15 min at 80 C but
  only Nytran can be dried at RT. 
  
 - To strip a blot: 3 X 5 min. at 80° C in 0.5% SDS; 40 mM Tris-HCl, pH 7.8. 
  
 - 0.25 M HCl = 5.1 ml conc. HCl in 250 ml total
  volume
 
  
Reagents for Alkaline TuroBlotting
Nytran 
  - Schleicher & Schuell membrane (0.2 µm
  pore size) 
  
 - 7 x 10 cm S&S # 77797
 
Denaturing Buffer:
  - 175.5 g = 3 M NaCl 
  
 - 16.0 g = 0.4 M NaOH 
  
 - 873 ml dH2O
 
Transfer Buffer:
(pH can be neutralized by CO2 - store air tight)
  - 175.5 g = 3 M NaCl 
  
 - 0.32 g = 8 mM NaOH
  
 - 0.63 g = 2 mM Sarkosyl 
  
 - 879 ml dH2O
 
5X Neutralizing Buffer:
1.0 M phosphate buffer, pH 6.8 
		
  - 79.5 g Na2HPO4 
  
 - 52.39 g anhydrous NaH2PO4
  
 - (or 60.25 g NaH2PO4*H2O)
  
 - bring to 1 L with water 
 
		
			
					
				
wick cover
					
					1 X wet buffer-wick*
					
					
					
					upper tray
					
					3X wet blotting paper*
					
					1 gel
					
					1 X wet Nytran
					
					1X wet blotting paper*
					4 X dry blotting paper
					
					20 X dry absorbent paper
					
					
					
					
					lower tray
		 
		
  
  
  * indicates prewet in transfer buffer
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  Context of Research Project
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© Copyright 2002 Department of Biology, Davidson College, 
Davidson, NC 28036
Send comments, questions, and suggestions to: macampbell@davidson.edu