Comparative in vivo analysis of the nsp15 endoribonuclease of murine, porcine and severe acute respiratory syndrome coronaviruses

► MHV nsp15 is distributed throughout the cytoplasm of virus-infected cells. ► MHV but not SARS-CoV or TGEV nsp15 formed speckles when ectopically expressed in cell. ► Two domains (I and III) within nsp15 are responsible for the speckle formation. ► A novel protein-interaction domain is identified in the C-terminus of MHV nsp15. ► nsp15s from the 3 coronaviruses have differential effects on MHV replication.