1. ¹Université de Lyon, Lyon, France; Université Lyon 1, Lyon, France
2. ²CNRS, UMR5534, Centre de Génétique Moléculaire et Cellulaire, Université Claude Bernard Lyon, Villeurbanne, France

Correspondence: Dr AL Epstein, Centre de Génétique Moléculaire et Cellulaire, CNRS-UMR 5534, Université Claude Bernard Lyon 1, 16 rue Raphaël Dubois—2nd floor, Villeurbanne, F-69622, France. E-mail: epstein@cgmc.univ-lyon1.fr

Received 9 December 2008; Revised 19 March 2009; Accepted 23 March 2009; Published online 16 April 2009.

Abstract

The last two years have seen significant advances in our understanding of the cellular innate responses elicited or activated by the entry of amplicon particles, which may, in part, explain the transient nature of transgene expression often observed in cells infected with helper-free amplicon stocks. At the technological level, the most consistent progress has been in strategies to enhance the stability of transgene cassettes, either through integration into host chromosomes or through the conversion of the amplicon genome into a replication-competent extrachromosomal element.