We report a novel strategy for constructing a tissue-targeting hemagglutinating virus of Japan (HVJ; Sendai virus) envelope vector (HVJ-E), and its application in gene therapy of a mouse model of
genetic skin disease. Chimeric genes encoding viral F
protein and
green fluorescent protein (GFP) were constructed on the basis of various deletion mutants. The product of one chimeric gene, containing
signal peptide, transmembrane domain, and the cytoplasmic tail of F
protein, was transported to the cell surface and incorporated into new viruses released from HVJ-infected LLC-MK2 cells. For tissue targeting, in the preceding construct GFP was replaced with single-chain antibody (scFv) against mouse
desmoglein 3 (mDsg3), a desmosomal
cadherin found in basal layer keratinocytes of the skin. HVJ encoding scFv-F chimeric
protein bound to mDsg3-coated plates much more efficiently than did wild-type HVJ. When chimeric HVJ was injected into a skin
blister of a mouse model of
epidermolysis bullosa, in which defective expression of
type VII collagen results in a failure to secure epidermis to the underlying dermis, viral F
protein expression was detected in most of the basal keratinocytes. Furthermore, chimeric HVJ-E introduced
type VII collagen expression more efficiently compared with wild-type HVJ in basal keratinocytes of
type VII collagen-deficient mouse skin, resulting in efficient amelioration of the genetic defect. Thus, a novel tissue-targeting HVJ-E could be used to successfully target epidermal keratinocytes both in vitro and in vivo.