Schematic representation of the Lenti-CMV-huVWF vector. This self-inactivating (SIN) lentiviral vector (11 kb) expresses the full-length human VWF cDNA (8.4 kb) from the human cytomegalovirus (CMV) promoter. The central polypurine tract (cPPT), which facilitates intranuclear import of the lentiviral preintegration complex, is depicted. The packaging signal (Ψ+) and viral long terminal repeats (LTRs) are indicated. The 3′ LTR contains a self-inactivating deletion which on transduction of the target cells is copied onto the 5′ LTR, rendering it inactive while preserving the activity of the internal CMV promoter.