FL As A Gene Transfer Vector

We have clarified that FL delivers their contents directly and efficiently into cytoplasm both in vitro and in v vo therefore, we applied FL to a gene transfer vector and attempted to solve the above problems. 

We examined the characteristics of FL as in comparison with CL-DNA complex, a common nonviral gene transfer vector. 

we examined the effect of the length of the exposure of the vectors to the cells on the gene transfer (Fig.3). L and HeLa cells were treated either with FL or with CL-DNA complex containing 0.5 pg of pCAL2 luciferase expressed plasmid, for 1, 10, or 30 min. Neither FL nor CL-DNA complex had any apparent cytotoxicity under these conditions. The cells 

We also examined the effect of serum proteins in the incubation medium on the gene transfer (Fig-4). FL efficiently transferred DNA in the presence of serum proteins. The cells incubated with FL in the presence of 40 % FCS still had 70 % of the luciferase activity of those incubated with the vector in the absence of serum proteins. On the contrary, serum proteins strongly inhibited the gene transfer mediated by CL-DNA complex. The cells incubated with CL-DNA complex in the presence of 5 % FCS showed no obvious luciferase activity compared with those incubated with the vector in the absence of serum proteins. 

The sensitivity of CL-DNA complex-mediated gene transfer to serum proteins may be due to the degradation of DNA by nucleases contained in the semm, because DNA formed an unstable complex with CL but was not encapsulated in the CL membrane. In contrast, DNA in FL was encapsulated in the membranous stmcture and protected from nucleases. Another possible explanation is that the absorption to the cell surface and/or the fusogenic activity of CL may be interfered by serum lipoproteins. The 

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