• One important principle is that all viral genomes must be copied to produce messenger RNAs (mRNAs) that can be read by host ribosomes.
  • A universal function of viral genomes is to specify proteins.


What information is encoded in the viral genome?

Gene products and regulatory signals for:

  • Replication of the viral genome
  • Assembly and packaging of the genome
  • Regulation and timing of the replication cycle
  • Modulation of the host defences
  • Spread to other cells and hosts

What information is not encoded in the viral genome?

  • genes encoding a complete protein synthesis machinery (e.g., no ribosomal RNA and no ribosomal or translation proteins); note: the genomes of some large DNA viruses contain genes for transfer RNAs (tRNAs), aminoacyl-tRNA synthetases, and enzymes that participate in sugar and lipid metabolism
  • genes encoding proteins of energy metabolism or membrane biosynthesis telomeres (to maintain genomes) or centromeres (to ensure segregation of genomes)
  • Probably we haven’t found them yet