The incorporation efficiency depends mainly on the usage of dTTP or dUTP (the incorporation efficiency of dTTP is slightly better than those for dUTP) and on the enzyme used for PCR. Regular Taq DNA polymerase incorporates dUTP (and especially labeled dUTP) less efficient than Taq DNA Polymerase with modified active center (Taq-T from Bioron, cat# 117005, 117025).
Applications
Fluorescent labelling of DNA by terminal deoxynucleotidyl transferase or DNA-polymerases
The regular protocol for DNA-labeling with Flu (TAMRA)-dUTP by PCR (ratio of labeled dUTP/nonlabeled:dTTP is 1:2):
Reagent |
Final concentration |
Quantity, for 50 µl of reaction mixture |
Sterile deionized water |
– |
variable |
10x PCR buffer |
1x |
5 µl |
10 mM dNTP Mix |
0.2 mM of each |
1 µl |
Flu (TAMRA)-dUTP, 1 mM |
0.1 mM |
5 µl |
Primer I |
0.1-1 µM |
variable |
Primer II |
0.1-1 µM |
variable |
Taq-T DNA Polymerase |
1.25 u -2.5 u/50 µl |
1.25 u -2.5 u |
100 mM MgCl 2 |
1-4 mM |
variable |
Template DNA |
10 pg-1 µg |
variable |
PCR should be performed as optimized on the regular dNTPs – with the same MgCl 2 concentration, with the temperatures and cycles optimized for the particular template and primers.