The cDNA library has been cloned into the multiple cloning site of pFB retroviral vector. Further, the splice-site configuration is optimized for expression from the viral 5' LTR promoter.
Libraries are available for functional screening.
Nonreplicating retroviral vectors contain all of the cis elements required to transcribe mRNA molecules that encode a gene of interest and to package these transcripts into infectious virus particles. Infectious virus particles that carry the cDNA library are created by transfecting specialized packaging cell lines. These cell lines are also referred to as producer cell lines. The env protein resides on the viral surface and interacts directly with cell type-specific receptors, thereby promoting infection of the target cell. The host range of the virus is dictated not by the DNA vector but by the choice of the env gene that is used to construct the packaging cell.