Methods for the construction of retroviral vectors and the generation of high-titer producers.

Retroviral vectors are powerful tools for gene transfer that are useful in the context of experimental as well as clinical applications. Defective recombinant retroviruses allow for efficient gene transfer into a broad range of mammalian cells derived from different species and different tissues. Safe gene transfer can be achieved using helper-free viral stocks, owing to the development of vectors and packaging cell lines that minimize the probability of hazardous recombination events. Retrovirus-mediated gene transfer leads to stable proviral integration in the target-cell genome, a key feature when the foreign genetic material must be faithfully transmitted to the progeny of the transduced parental cell, murine leukemia virus (MLV)-based vectors accommodate numerous modifications, thus providing a plastic tool that can be tailored for very diverse applications.