THE DESIGN AND
CHOICE OF TFO BINDING HBV CORE PROMOTER TO FORM TRIPLEX DNA
Guang LX, Li WM, Yuan FH, Xi M, Ai YP
Xinqiao Hospital, Chongqing, China
Objective: To choose triple helix-forming
oligodeoxyribo-nucleotide (TFO) that might bind HBV core promoter target
site with high affinity and specificity, so that we could go on subsequent
experiments: inhibiting HBV gene transcription.
Methods: Similar homopurine domain (1734-1754) in HBV
core promoter was chosen as target sequence. Several corresponding TFOs
were synthesized. TFO affinity and specificity binding to target sequence
were tested by electrophoretic mobility shift and Dnase 1 footprinting
assays.
Results: At
37? and pH 7.4 condition, CT-TFO,
GT-TFOp bound the target
sequence weakly with Kd values ??10-6M; The affinity of GT-TFOap and
AG-TFOsh binding to the target was higher than that of formers, with Kd
values of 5?10-7M and 2.5?10-8M respectively; AG-TFOl had the highest
binding affinity(Kd value: 3?10-9M) in all TFOs with a sequence specific
manner.
Conclusion: TFO containing AG or GT could bind
homopurine in HBV core promoter in adverse parallel direction to form
triple helix. AG-TFOl had the highest binding affinity in all TFOs studied
and bound target sequence completely.
It could be used as repressor of HBV gene transcription after
modified.