ADAR-editing during Ostreid herpesvirus 1 infection in Crassostrea gigas: facts and limitations

• Published in: mSphere
• Main Authors: Umberto Rosani, Enrico Bortoletto, Caroline Montagnani, Paola Venier
• Other Authors: Rosani, Umberto, Bortoletto, Enrico, Montagnani, Caroline, Venier, Paola
• Format: Article in Journal/Newspaper
• Language: English
• Published: AMER SOC MICROBIOLOGY 2022
• Subjects: ADAR1; hyper-editing; oyster; OsHV-1; antiviral immunity; Crassostrea gigas
• Online Access: http://hdl.handle.net/11577/3420297; https://doi.org/10.1128/msphere.00011-22

Ostreid herpesvirus-1 (OsHV-1) RNAs are enzymatically modified by A-to-I conversions during the infection of Crassostrea gigas. The increase of ADAR1 expression and hyper-editing activity parallel to OsHV-1 RNAs suggests a functional connection between dsRNA editing and antiviral responses. We analyzed 87 RNA-seq datasets from immuno-primed, resistant, and susceptible oysters exposed to OsHV-1 to compare the ADAR hyper-editing levels on host and viral transcripts and trace hyper-editing on the oyster genes. Host RNAs were more hyper-edited than viral RNAs, despite the increased editing of viral RNAs in late infection phases. A set of genes, representing ~0.5% of the oyster transcriptome and including several Tripartite motif-containing sequences, were constantly hyper-edited. Conversely, we identified genes involved in antiviral response, miRNA maturation and epigenetic regulation which were hyper-edited in specific conditions only. Despite technical and biological bottlenecks that hamper the understanding of the bivalve ‘RNA editome’, available tools and technologies can be adapted to bivalve mollusks.