Protein transduction by pseudotyped lentivirus-like nanoparticles

A simple, efficient and reproducible method to transduce proteins into mammalian cells has not been established. Here we describe a novel protein transduction method based on a lentiviral vector. We have developed a method to package several thousand foreign protein molecules into a lentivirus-like nanoparticle (LENA) and deliver them into mammalian cells. In this proof-of-concept study, we used beta-lactamase (BlaM) as a reporter molecule. The amino-terminus of BlaM was fused to the myristoylation signal of lyn, which was placed upstream of the amino-terminus of Gag (BlaM-gag-pol). By co-transfection of plasmids encoding BlaM-gag-pol and vesicular stomatitis virus-G (VSV-G) into 293T cells, LENA were produced containing BlaM enzyme molecules as many as Gag per capsid, which has been reported to be similar to 5000 molecules, but lacking the viral genome. Infection of 293T and MT-4 cells by VSV-G-pseudotyped BlaM-containing LENA led to successful transduction of BlaM molecules into the cell cytoplasm, as detected by cleavage of the fluorescent BlaM substrate CCF2-AM. LENA-mediated transient protein transduction does not damage cellular DNA, and the preparation of highly purified protein is not necessary. This technology is potentially useful in various basic and clinical applications. Gene Therapy (2011) 18, 936-941; doi:10.1038/gt.2011.38; published online 31 March 2011