¹Center for Virology and Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA

Correspondence: Professor BR Cullen, Center for Virology and Department of Molecular Genetics and Microbiology, Box 3025, Duke University Medical Center, Durham, NC 27710, USA. E-mail: culle002@mc.duke.edu

Received 1 June 2005; Revised 15 August 2005; Accepted 31 August 2005; Published online 29 September 2005.

Abstract

Over the last years, RNA interference (RNAi) has become a widely used technique that permits the knock-down, and hence functional analysis, of individual genes in vertebrate cells. However, the high failure rate of the RNA molecules used in RNAi experiments continues to be a problem. In this paper, I describe a set of design criteria, experimental steps and expression vectors that can facilitate the effective knock-down of almost any vertebrate gene product in cultured cells or in experimental animals.