A chimeric peptide of recombinant human fibronectin fragments produced in E. coli, consisting of three functional domains: a central cell-binding domain (type III repeat, 8–10), heparin-binding domain II (type III repeat, 12–14), and a CS1 site within the alternatively-spliced IIICS region. It is a 574 amino acid protein with a molecular weight of 63 kDa. When coated on the surface of containers such as culture dishes, petri dishes, flasks or bags, RetroNectin significantly enhances retrovirus-mediated gene transduction into mammalian cells. This enhancement is hypothetically due to colocalization of retroviral particles and target cells on the molecules of RetroNectin. Virus particles bind RetroNectin via interaction with heparin-binding domain II, and target cells bind mainly through the interaction of the cell surface integrin receptor VLA-4 with the fibronectin CS1 site. 0.5mg