Retrovirus-mediated gene transfer into adult skin fibroviral LTR promoter (LASN) were compared for their ability blasts has provided measurable amounts of therapeutic to express ADA from transduced primary rat skin fibroproteins in animal models. However, the major problem blasts in vivo. Skin grafts formed from fibroblasts transemerging from these experiments was a limited time of duced with LNFnA showed strong human ADA enzyme vector encoded gene expression once transduced cells activity from 1 week to 3 months. In contrast, skin grafts were engrafted. We hypothesized that sustained trans-containing LASN-transduced fibroblasts tested positive for duced gene expression in quiescent fibroblasts in vivo human ADA for weeks 1 and 2, were faintly positive at might be obtained by using a fibronectin (Fn) promoter.week 3 and showed no human ADA expression at 1, 2 and Fibronectin plays a key role in cell adhesion, migration and 3 months. Thus, a fibronectin promoter provided sustained wound healing and is up-regulated in quiescent fibroblasts.transduced gene expression at high levels for at least 3 Retroviral vectors containing human adenosine deaminase months in transplanted rat skin fibroblasts, perhaps permit-(ADA) cDNA linked to rat fibronectin promoter (LNFnA) or ting the targeting of this tissue for human gene therapy.