Identification of simian varicella virus gene 21 promoter region using green fluorescent protein

Clinical, pathological, immunological and virological features of simian varicella virus (SVV) infection in primates closely resemble those of varicella zoster virus (VZV) infection in humans. In ganglia infected latently of humans and monkeys, gene 21 of VZV and SVV is transcribed, respectively. We determined the nucleotide sequence of the intragenic region between SVV genes 20 and 21 to identify the putative promoter region for SVV gene 21. A recombinant clone was prepared in which the gene encoding green fluorescent protein (GFP) was inserted ten base pairs upstream of the predicted translational start site for SVV gene 21. SVV-infected monkey kidney cells transfected with the recombinant clone showed the presence of green fluorescence, whereas transfection of these cells with a construct containing the GFP gene in the opposite orientation, produced no fluorescence. The recombinant clone containing GFP flanked by SVV sequences can be used to prepare a SVV mutant in which the virus gene 21 promoter drives GFP. Such a mutant will be useful in analyzing varicella pathogenesis and latency in experimentally infected animals, studies not possible in humans.