A SUBGENOMIC MESSENGER-RNA TRANSCRIPT OF THE CORONAVIRUS MOUSE HEPATITIS-VIRUS STRAIN A59 DEFECTIVE INTERFERING (DI) RNA IS PACKAGED WHEN IT CONTAINS THE DI PACKAGING SIGNAL

In infected cells, only the genomic RNA of the coronavirus mouse hepat itis virus strain A59 (MHV-A59) is packaged into the virions, In this study, we show that a subgenomic (sg) defective interfering (DI) RNA c an be packaged into virions when it contains the DI RNA packaging sign al (DI RNA-Ps). However, the sg DI RNA is packaged less efficiently th an the DI genomic INA, Thus, while specificity of packaging of RNAs in to MHV-A59 visions is determined by the DI RNA-Ps, efficiency of packa ging is determined by additional factors.