Objective To amplificate,clone and sequence the thymidine kinase (TK) gene of herpes simplex virusⅡ(HSVⅡ); to construct and appraise the fusion gene eukaryon expression vector, pcDNA3/HSVⅡ TK/angiostatin. MethodsThe Hep2 cells were infected by HSVⅡ Sav strain. HSVⅡ genomic DNA was purified from the Hep2 cells suspension and used as template to run PCR for TK gene amplification. The amplified products were cloned into PC DNA3 vector and sequenced. The vector pcDNA/HSVⅡ TK was cut by endonuclease. The gained TK gene was cloned into eukaryon expression vector. pcDNA3/angiostation, which had been constructed. ResultsCoding region of HSVⅡTK gene consisted of 1 128 bp except stop code, it encoded 376 amino acids.After cutting the new vector by endonuclease Hind Ⅲ and BamH Ⅰ,we gained the following gene fragment: 1000 bp (TK) and 700 bp (angiostation).Conclusion The fusion gene eukaryon expression vector， pcDNA3/HSVⅡ TK/angiostatin has been constructed.
【Abstract】ObjectiveSome studies have demonstrated that recombinant adenoviruses are efficient vectors for gene transfer to the venous wall and AdCMV.tk encoded thymidine kinase can be used to reduce restenosis. In this study AdCMV.tk was apply to human vein smooth muscle cells (SMC) and organ cultured saphenous veins to study its effects on proliferation of SMCs and reduction of intimal hyperplasia. MethodsThe adenovirus vector transferred tk gene and mark gene lacZ to the SMC of human saphenous veins and organ cultured vein segments. Various concentrations ganciclovir (GCV) were contained in culture media. The efficiency of gene transfer was studied by using Xgal staining. The proliferation of SMC was monitored by the method of trypan blue exclusion. The bystander effect was observed by mixed cell culture. After vein segments treated by AdCMV.tk+GCV and cultured for 14 days, HE and VG staining were carried out and intimal thickness was analysis by computer image system. ResultsAdenovirus vector could infect saphenous vein SMC efficiently both in cultured SMCs and organ cultured vein segments. Gene expression sustained 14 d at least. The inhibition of SMCs proliferation in vitro was a positive correlation in GCV concentrations and the levels of tk expression. The proliferation of SMCs transfectered lacZ wasn’t restrained by GCV (P＜0.05). In mixed cell experiment there was at least 55% reduction in total cell number when as few as 10% of the cells express tk. Assessment of this “suicide gene strategy” in saphenous vein organ culture model demonstrated that veins treated with AdCMV.tk+GCV had a significant reduction at 14 days in the intimal thickness compared to control group (P＜0.01). ConclusionThe results suggest that adenovirusmediated gene transfer of tk along with GCV administration may be a useful strategy to treat the proliferation of intimal hyperplasia of transplanting saphenous veins. Bystander effects are amplified by AdCMV.tk/GCV gene therapy system.