Coy, Samantha R.Utama, BudiSpurlin, James W.Kim, Julia G.Deshmukh, HarshavardhanLwigale, PeterNagasaki, KeizoCorrea, Adrienne M. S.2023-04-252023-04-252023Coy, Samantha R., Utama, Budi, Spurlin, James W., et al.. "Visualization of RNA virus infection in a marine protist with a universal biomarker." <i>Scientific Reports,</i> 13, (2023) Springer Nature: https://doi.org/10.1038/s41598-023-31507-w.https://hdl.handle.net/1911/114853Half of the marine virosphere is hypothesized to be RNA viruses (kingdom Orthornavirae) that infect abundant micro-eukaryotic hosts (e.g. protists). To test this, quantitative approaches that broadly track infections in situ are needed. Here, we describe a technique—dsRNA-Immunofluorescence (dsRIF)—that uses a double-stranded RNA (dsRNA) targeting monoclonal antibody to assess host infection status based on the presence of dsRNA, a replicative intermediate of all Orthornavirae infections. We show that the dinoflagellate Heterocapsa circularisquama produces dsRIF signal ~ 1000 times above background autofluorescence when infected by the + ssRNA virus HcRNAV. dsRNA-positive virocells were detected across > 50% of the 48-h infection cycle and accumulated to represent at least 63% of the population. Photosynthetic and chromosomal integrity remained intact during peak replication, indicating HcRNAV infection does not interrupt these processes. This work validates the use of dsRIF on marine RNA viruses and their hosts, setting the stage for quantitative environmental applications that will accelerate understanding of virus-driven ecosystem impacts.engThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.Journal articles41598-023-31507-whttps://doi.org/10.1038/s41598-023-31507-w