Cover photograph: Reporter systems are useful to visualize and quantify viral replication and spread. Viruses often encode proteases, which are required for viral protein maturation. Pahmeier et al. describe a reporter system composed of an endoplasmic reticulum (ER)-anchored fluorescent protein fused to a nuclear localization sequence that, upon cleavage by a viral protease, is released from the ER and translocated into the nucleus. The modular system was used to generate reporter cell lines to detect infection from two major human pathogens, dengue virus and SARSCoV-2. Shown is a reporter cell at different times after infection. Green fluorescent protein nuclear signal increases as infection progresses. (See related article in February 2021, vol. 95, no. 4, e01715-20.) (Copyright © 2021 American Society for Microbiology. All Rights Reserved.)