%0 Journal Article
%T Construction of Metabolically Biotinylated Adenovirus with Deleted Fiber Knob as Targeting Vector
%A Yanzheng Liu
%A Philippe Valadon
%A Jan E Schnitzer
%J Virology Journal
%D 2010
%I BioMed Central
%R 10.1186/1743-422x-7-316
%X The hAd5-based vector remains one of the most popular vector systems for gene delivery and cancer gene therapy. However, the ubiquitous expression of adenoviral primary receptor CAR in many tissues and the predominant liver tropism of the vector after systemic administration limit the application of hAd5 vector to clinical use [1]. Therefore, strategies to re-direct hAd5 infection and to decrease the rapid uptake of the virus by the reticuloendothelial system (RES) will be essential for many gene therapy applications. The hAd5 binds to most cell types through the interaction of its fiber knob domain with cell surface CAR [2]. Retargeting of the hAd5 vector appears to be more effective when the transduction mediated by retargeting ligands is directed through the fiber protein [3]. The adenoviral capsid proteins, especially fiber knob and hexon, associate with blood factors and mediate hepatocyte transduction in vivo [4-8]. The binding of hAd5 hexon protein with coagulation factor FX plays a major role in hepatocyte infection in vivo [4-6]. Single point mutation within the hexon hypervariable regions effectively blocks FX-mediated adenoviral hepatocyte transduction in vitro and in vivo [7]. The hAd5 fiber knob domain binds coagulation factor IX and complement component C4-binding protein that bridge the virus to cognate receptors on hepatocytes [8]. In the same study, a modified adenoviral vector with fiber knob mutations was shown to have less accumulation in both hepatocyte and Kupffer cells. Therefore, both the fiber and hexon proteins need to be modified to retarget adenoviral vector away from the liver.In the study reported here, we have ablated the native tropism of hAd5 by removing the fiber knob and part of the central shaft. We have added to the short fiber a truncated form of PSTCD as a biotin acceptor protein to allow the virus to be metabolically biotinylated. We demonstrated here that the N-terminal tail and 9 shaft repeats fused with PSTCD protein can be
%U http://www.virologyj.com/content/7/1/316