XRN1-Resistant Elements Are Located in the 3'-Terminal Regions of Certain Genome Segments of Jingmenviruses.

Jingmenviruses have been identified over the past decade. During this period, significant advancements have been made in understanding their diversity, biology, and genomic functionality. Conventionally characterized orthoflaviviruses are distinguished by a specific class of subgenomic RNAs (sfRNAs) that contain exoribonuclease-resistant RNA (xrRNA) structures. These sfRNAs are the products of incomplete 5'-3' degradation of genomic RNA by the host exoribonuclease XRN1. Resistance to complete hydrolysis is mediated by highly conserved secondary structural motifs localized within the 3' untranslated region (UTR) of the genomic RNA. In classical orthoflaviviruses, xrRNAs play key roles in regulating viral replication, modulating the host immune response, and driving host cell adaptation. In the present study, we evaluated the exonuclease resistance of the 3' UTR genomic RNA segments of Alongshan and Yanggou viruses using in vitro assays. Our results demonstrate that 1 and 4 segments of Alongshan virus and 3 and 4 segments of Yanggou tick virus exhibit resistance to XRN1-mediated degradation.