The use of herpes simplex virus (HSV) vectors for gene chondroitin ABC lyase, HSV infection was restored, which delivery to skeletal muscle is hampered by a maturationsuggests that virus secondary receptors were present but dependent loss of muscle fiber infectivity. Previous studies not readily accessible to the virus in the intact myofiber. of HSV type 1 (HSV-1) infection in the rodent show that Surprisingly, we also found that HSV-1 infectivity could be the loss of infectivity may be due, at least in part, to the restored in vitro and in vivo by exposing myofibers to low development of the basal lamina throughout the course of concentrations of the glycosaminoglycan analog dextran maturation, which may block the initial events in HSV infecsulfate, which appears to act as a surrogate receptor to tion. To initiate infection, HSV normally attaches to cell surstabilize the virus at the myofiber surface such that HSV face heparan sulfate, which stabilizes the virus such that can engage additional receptors. This demonstration that it can interact with secondary protein receptors required the basal lamina is not an absolute block to HSV-1 infecfor entry into host cells. In this study, we demonstrate that tion is remarkable because it allows for the nondestructive heparan sulfate biosynthesis is downregulated during skeltargeting of HSV-1 to mature myofibers and greatly etal muscle maturation. When myofibers were treated with expands the usefulness of HSV as a gene therapy vector a variety of enzymes, including collagenase type IV or for the treatment of inherited and acquired diseases.