Vectors derived from retroviruses are useful tools for long-term gene transfer because they allow stable integration of transgenes and propagation into daughter cells. Lentiviral vectors are preferred because they can transduce non-proliferating cellular targets. These vectors can be engineered to target specific tissues. In the Cold Spring Harbor Protocols, François-Loïc Cosset and colleagues from Ecole Normale Supérieure de Lyon present a method for targeting hematopoietic stem cells using engineered viral vectors. The article, "Hematopoietic Stem Cell Targeting with Surface-Engineered Lentiviral Vectors," is at (http://cshprotocols.cshlp.org/cgi/content/full/2009/8/pdb.prot5276).
Though viral vectors are highly efficient, their use can raise concerns about recombination, immune responses, and other safety issues. DNA transposons offer an effective, alternative method for nonviral gene transfer that avoids the safety concerns associated with viral vectors. Use of the "Sleeping Beauty Transposon System for Stable Gene Expression in Mouse Embryonic Stem Cells" from Catherine Krull and colleagues at the University of Michigan (http://www.med.umich.edu/cdb/sub_pages/People/krull.htm) provides a method for stable integration and reliable long-term expression of a transgene. Sleeping Beauty transposon-based transfection is a two-component system consisting of a transposase and a transposon containing inverted repeat/direct repeat sequences that result in precise integration into a TA dinucleotide. The article is freely accessible on the website for Cold Spring Harbor Protocols (http://cshprotocols.cshlp.org/cgi/content/full/2009/8/pdb.prot5270).
Source: Cold Spring Harbor Laboratory