Cytomegalovirus replicon-based regulation of gene expression in vitro and in vivo.
There is increasing evidence for a connection between DNA replication and the expression of adjacent genes. Therefore, this study addressed the question of whether a herpesvirus origin of replication can be used to activate or increase the expression of adjacent genes. Cell lines carrying an episomal vector, in which reporter genes are linked to the murine cytomegalovirus (MCMV) origin of lytic replication (oriLyt), were constructed. Reporter gene expression was silenced by a histone-deacetylase-dependent mechanism, but was resolved upon lytic infection with MCMV. Replication of the episome was observed subsequent to infection, leading to the induction of gene expression by more than 1000-fold. oriLyt-based regulation thus provided a unique opportunity for virus-induced conditional gene expression without the need for an additional induction mechanism. This principle was exploited to show effective late trans-complementation of the toxic viral protein M50 and the glycoprotein gO of MCMV. Moreover, the application of this principle for intracellular immunization against herpesvirus infection was demonstrated. The results of the present study show that viral infection specifically activated the expression of a dominant-negative transgene, which inhibited viral growth. This conditional system was operative in explant cultures of transgenic mice, but not in vivo. Several applications are discussed.
Max von Pettenkofer-Institute, Ludwig-Maximilians-Universität München, Munich, Germany.
Hermine
H
Mohr
Christian A
CA
Mohr
Marlon R
MR
Schneider
Laura
L
Scrivano
Barbara
B
Adler
Simone
S
Kraner-Schreiber
Angelika
A
Schnieke
Maik
M
Dahlhoff
Eckhard
E
Wolf
Ulrich H
UH
Koszinowski
Zsolt
Z
Ruzsics
D000818:Animals; D015153:Blotting, Western; D003587:Cytomegalovirus / Q000235:genetics*; D003586:Cytomegalovirus Infections / Q000235:genetics*; D015967:Gene Expression Regulation, Viral / Q000235:genetics*; D017930:Genes, Reporter; D017404:In Situ Hybridization, Fluorescence; D051379:Mice; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D018146:Muromegalovirus / Q000235:genetics*; D041681:NIH 3T3 Cells; D012093:Replicon / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction