Genome structure of mouse hepatitis virus: comparative analysis by oligonucleotide mapping

Area of Science:

• Virology
• Molecular Biology
• Genetics

Background:

• Mouse hepatitis virus (MHV) is a significant pathogen with diverse natural variants.
• Understanding the genetic relatedness and variations among MHV strains is crucial for studying viral pathogenicity.

Purpose of the Study:

• To compare natural variants of mouse hepatitis viruses using T1-oligonucleotide fingerprinting.
• To identify genetic differences and similarities between specific MHV strains and plaque variants.
• To map unique oligonucleotides to specific regions of the MHV genome.

Main Methods:

• T1-oligonucleotide fingerprinting technique was employed to analyze MHV variants.
• RNA mapping was performed to locate specific oligonucleotides within the viral genome.
• Comparison of genomic sequences of different MHV strains and plaque variants.

Main Results:

• Most MHV variants showed extensive divergence, with notable exceptions like the relatedness of hepatotropic MHV-3 and nonpathogenic A59 strains.
• MHV-3 and A59 strains each contained 2-4 unique oligonucleotides, with some mapped near the 5' and 3' ends of the genome, potentially linked to pathogenicity.
• Two JHM plaque variants (DL and DS) shared most oligonucleotides but had one unique spot each, with the DL-specific oligonucleotide mapped near the 3' end.
• The MHV genome was confirmed to possess a 'cap' structure, characteristic of positive-stranded RNA viruses.

Conclusions:

• T1-oligonucleotide fingerprinting is effective in revealing genetic relationships and variations among MHV strains.
• Specific genetic regions, identified by unique oligonucleotides, may play a role in MHV pathogenicity and phenotypic variation.
• The MHV genome structure is consistent with a positive-stranded RNA virus.