BIOL 4190 Lecture Notes - Lecture 1: T7 Rna Polymerase, Double-Stranded Rna Viruses, Rna-Dependent Rna Polymerase
Document Summary
Describe the structural features of the influenza virus. Enveloped, (8) segmented (-) rna circular/spherical genome (filamentous when initially isolated, spherical after passing through cells) Contains hemagglutinin (h) antigen glycoprotein spikes on the surface, neuraminidase (n) antigen spikes, and m2 ion channel protein. H protein and low-ph dependent membrane fusion. H protein must be cleaved by cellular proteases for the virus to be infectious. Transcription complexes are initially released into the cytoplasm - then enter the nucleus. Transcription occurs in nucleus, replication also occurs in the nucleus. Transcripts have 5" cap and 3" polyadenylation. 5" cap of mrna transcript has viral pb2 protein attached along with host mrna nucleotides - cap-snatching process. Viral pb2 snatches the host cap nucleotides - function as the primer for transcription - host genome primer. Complex pa and pb1 dissociate from pb2 - create the poly-a tail of the transcripts - viral genome polyadenylation. Replication and transcription creates (+) rna from (-) rna genome.
