Genomic and subgenomic RNAs of rabbit hemorrhagic disease virus are both protein-linked and packaged into particles

The major subgenomic RNA of the calicivirus rabbit hemorrhagic disease virus which codes for the viral capsid protein has been cloned as cDNA. The nucleotide sequence of this mRNA was shown to be identical to the 3′ terminal region of the genomic RNA. The 5′ end of the mRNA corresponds to position 5296 of the genomic sequence; except for two differences the first 16 nucleotides of genomic and subgenomic RNAs are identical. After isolation from liver tissue viral genomic and subgenomic RNAs were found to be resistant to RNase degradation. This protection was due to RNA packaging into particles. Sucrose density gradient centrifugation of liver homogenates allowed separation of such particles containing either genomic RNA or subgenomic RNA. Genomic and subgenomic RNAs are protein-linked and for the genomic molecule this interaction is localized within the first 179 nucleotides. After radioactive labeling of purified RNA and subsequent RNase treatment a protein of 15 kDa was identified.