[Effect of 3' exonuclease activity of polymerase on extension of phosphorothioate-modified primers].
OBJECTIVE
To determine whether 3'phosphorothioate-modified-2 terminal mismatched primers can turn off DNA polymerization mediated by Exo(+) polymerase.


METHODS
Two-directional primer extension was performed using polymerase with and without 3' exonuclease activity. The effects of unmodified primers and 3' phosphorothioate-modified primers on primer extension were evaluated.


RESULTS
Exo(-) polymerase yielded products from matched and mismatched primers regardless of their modification. However, 3' phosphorothioate-modified primers with a single base mismatch at -2 position worked similarly to the terminal (-1) mismatched primers in triggering the novelly reported "off-switch" of Exo(+) polymerase.


CONCLUSIONS
These data suggested that the "off-switch" can be of enormous application in the diagnosis of single gene diseases and in the association studies by single nucleotide polymorphism screening.
Guo
Zi-fen
ZF
Department of Pharmacy and Pharmacology, Nanhua University, Hengyang, Hunan, 421001 PR China.
Chen
Lin-ling
LL
Zhang
Jia
J
Peng
Cui-ying
CY
Yang
Xiang-dong
XD
Zhang
Xu
X
He
Shu-ya
SY
Liao
Duan-fang
DF
Li
Kai
K
D017931:DNA Primers / Q000737:chemistry / Q000235:genetics*; D005092:Exonucleases / Q000378:metabolism*; D006801:Humans; D054735:Phosphorothioate Oligonucleotides / Q000737:chemistry / Q000235:genetics*; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide
D017931:DNA Primers; D054735:Phosphorothioate Oligonucleotides; D005092:Exonucleases