Loss of nsp14-exonuclease activity impairs the replication, proofreading, fitness, and pathogenesis of SARS-CoV-2. - Anderson-Daniels J; Diefenbacher MV; Yount BL; Meganck RM; Tse LV; Burke KN; Miranda HA; Scobey DT; Lu X; Stevens L; Dinnon KH 3rd; Chapman NS; et al. (MBio, 2026)