Preparation of gel for Posi blot transfer

1. Cut gel to size of preexisting mask or cut new mask.
   
2. For depurination: put gel in pyrex dish, add 500ml .25N HCl (10mL conc. HCl+450ml H2O) and shake 15min.
   
3. Remove HCl, rinse w/H2O
   
4. Add 500ml 1X Posiblot denaturing solution and shake 15min.
   
5. Repaeat #4
   
6. Remove denaturing solution
   
7. Add 500ml Posi blot neutralizing solution and shake 15min.
   
8. Repeat #7
   
9. While gel is in 2nd neutralizing wash (step 8):
   a) make up 1 liter 5XSSPE
   b) cut gene screen plus membrane to size of gel and mark membrane w/pen
   c) cut whatman larger than size of gel
   d) soak gene screen plus and sponge in 5XSSPE