ABSTRACT
Molecular details of viral pathogenesis have been explored at an amazing speed over the past decade. Previously, viruses had been viewed as genetic parasites that exploit cellular metabolism in order to propagate themselves. To usurp the infected cell viruses have evolved various strategies to shut down synthesis of cellular macromolecules and direct the cell machinery to produce viral material. Over millions of years of virus and host coevolution there has been plenty of time for the development of very complex and intimate interactions between the two. Studies on latent and persistent viruses in particular have shown that viruses have developed extremely sophisticated strategies to manipulate the host’s cellular regulation in order to transform host cells, replicate, or persist. Cellular homeostasis in multicellular organisms is directed by extracellular signals. Not surprisingly, to exercise total control over host cells, viruses have evolved numerous genes that function as signal interceptors or activators. Some of these genes are of host origin, as shown by homology searches, others may have arisen by convergent evolution (Murphy, 1994; Smith, 1994). In addition to helping us understand viral pathogenesis, these studies provide further insight into cellular regulation.
