Specificity of Viral Gene Controlling Elements in Transgenic Mice

Abstract

Among the many facets of viral pathogenesis, one of particular interest to the molecular biologist is the ability of the virus to adapt its mechanisms for gene control to specific host environments. Although we may be accustomed to analyze viral gene regulation in cultures of cells that are permissive for a given virus or suitable for transfection with cloned gene constructs, in the living organism the virus associates itself with cells that may be quite different from those in the Petri dish. Why does one virus single out the brain, another the respiratory system, a third one the intestinal tract? This complex problem of viral tissue tropism has been the topic of previous contributions to this series (see Concepts in Viral Pathogenesis, Vol I, Chapters 11, 15, and 19). New clues have come from studies of viral gene controlling elements and their role in the selection of target tissues in the animal. These viral control sequences, also called enhancers are thought to interact with specific host factors to regulate the transcription of genes that are under their influence. The reader is referred to Chapter 8 in this volume for details. Here, the focus will be on the expression in transgenic mice of genes that are under the control of viral enhancers.