Orthomyovirdae

• Is helical, -SSRNA, linear segmented, enveloped virus
• with viral stratagies

  • Cap snatiching
  • alternative splicing
  • NP binding to viral genome
• two major envelope proteins are Hemagglutinin and Neuromidase. HA will bing host receptors salic acid, and NA is needed for viral egression.
• only H1-H3 and N1 N2 will effect humans
• Ribsonuceloprotein has 8 ribonucleoproteins which are -ssRNSA coated in nucleocapsid proteins therefore a tripartite polymerase composed of PA, PB1, PB2, are at each end
• What is cap snatching?

  Cap snatching is a mechanism used by viruses to steal the 5' end of host mRNA molecules to initiate viral protein synthesis.

  the tripartite (PA,Pb1, Pb2) will associate with the 5' cap and then with pb2 bind to the subunit, PA is an endonuclease so it cleaves the cap off after a purine (A/G) and then it is ligated on the viral mRNA
• Transcription genome replication regulation: influenza transcription and genome replication happen in the host nucleus while translation occurs in the cytoplasm. to switch from the transcription of genome replication the NPC must bind to the viral genome to increase the synthesis of anti-genome M1 or M2 to increase coding capacity.
• Alternate RNA splicing is when segments 7 and 8 undergo alternative splicing. mRNA from seg 7 could have two outcomes:

  M1 the main matrix protein or M2 the ion channel.