Nuclear targeting of DNA

The nuclear membrane is a tight barrier for cytoplasmic proteins, but nucle ar proteins have the intrinsic ability to overcome this barrier by an activ e signal-mediated process. Specific cytoplasmic carrier proteins have the r esponsibility to escort these proteins into the nucleus through the nuclear pore. The nuclear membrane is also a tight barrier for exogenous DNA deliv ered by synthetic vehicles, while many of the karyophilic viruses have a me chanism to actively deliver their genome through the nuclear pore. Virus DN A and RNA cannot move into the nucleus by themselves and require the viral structural proteins for efficient nuclear transport. In this article, we re view the recent progress in understanding the mechanism of the nuclear tran sport of proteins and the virus genome, and discuss the possibility of deve loping synthetic gene-delivery systems based on these outcomes. (C) 2001 El sevier Science B.V. All rights reserved.