Assays for HSV Gene Expression During Establishment and Maintenance of Latent Infection

Assays in use for the analysis of herpes simplex virus (HSV) gene expression during the establishment and maintenance phases of infection in the nervous system include: 1 The use of reporter genes, for example, the lacZ gene from Escherichia coli, which is inserted by homologous recombination into the viral genome, and which may be driven either by viral promoters or by an exogenous promoter, such as the major immediate early (IE) promoter of cytomegalovirus. In our hands, the detection of lacZ activity in neuronal tissue infected with recombinant HSV constructs has proven to be a simple and effective means of monitoring viral activity in the peripheral nervous system. 2. Analysis of virally encoded RNA transcripts, either by in situ hybridization (ISH) using radioactive or nonradioactive indicator molecules, or by Northern analysis (this technique is described in Chapters 13 and 24 ). 3. Immunohistochemistry to demonstrate the presence of viral proteins, which technique can also be used in combination with ISH (dual labeling).