FIGURE 10.

Cytoplasmic transcription by RNA polymerase III in innate immune defense. Upon infection (1), the varicella zoster virus (VZV) DNA is found in the nucleus and the cytoplasm (Mahalingam et al., 1999; Zerboni et al., 2014). Although not specifically reported for VZV, cytoplasmic liberation of DNA from capsids may involve proteasomal degradation (2), as was described for herpes simplex virus 1 (HSV-1; Horan et al., 2013). Cytoplasmic AT-rich VZV DNA is transcribed by Pol III (3), the 5′ tri-phosphorylated RNA folds into stem-loop structures, interacts with the retinoic acid-inducible gene I (RIG-I) (4), which, via mitochondrial antiviral signaling (MAVS) protein and NF-kB/IRF3 transcriptional activators (5) increases transcription of type I interferon genes (6).