Q vectors, bicistronic retroviral vectors for gene transfer

We have developed a retroviral vector that incorporates unique features of some previously described vectors. This vector includes: 3' long terminal r epents (LTRs) of the self-inactivating class; a 5' LTR that is a hybrid of the cytomegalovirus (CMV) enhancer and the mouse sarcoma virus promoter; nn internal CMV immediate early region promoter to drive expression of the tr ansduced gene and the neomycin phosphotransferase selectable marker an expa nded,multiple cloning site and an internal ribosome entry site. An SV40 ori was introduced into the vector backbone to promote high copy number replic ation in packaging cell lines that express the SV40 large T antigen. We dem onstrate that these retrocil al constructs, designated Q vectors, can be us ed in applications where high viral titers and high level stable or transie nt gene expression are desirable.