Fundamental properties of viruses
viral genomes are packaged inside particles that mediate their transmission from cell to cell
• the viral genome contains the information for initiating and completing an infectious cycle
• viruses establish themselves in a host population to ensure virus survival
Plus (+) and minus (-) strand definition
Information encoded by the virus
Hallmarks of the infectious cycle
Permissive vs susceptible
General overview of an infectious cycle
Overview of different replication strategies
Group I
Group I – Polyomaviridae characteristics
Group I – Polyomaviridae replication
Group I – lytic vs. latent infections
Like all herpesviruses, herpes simplex virus 1 (HSV1) is able to produce lytic or latent infections depending on the host cell type. Lytic infections occur in a broad range of cells while latency is highly specific for neurons.
Lytic infection refers to the situation in which the virus replicates in a host cell and causes its lysis, releasing hundreds to thousands of progeny virions. A latent infection is quite different. Here the virus enters into a refractory state in which little or no progeny virus is produced and the cell is not immediately damaged. The virus DNA is present in the latently infected cell nucleus, but there is little DNA replication and only minimal expression of virus-encoded genes. The virus can be reactivated from latency following an appropriate stimulus, however, and reactivation causes lytic virus replication
Group II
single stranded DNA viruses
Group II – Parvoviridae characteristics
Group II – Parvoviridae replication
RNA virus replication strategies
(+) strand viral RNA genome
(-) strand viral RNA genome
ds viral RNA genome
ss viral RNA genome with DNA intermediate stage
RNA virus replication strategy w/o DNA stage
RNA virus replication strategy with DNA stage
Group III
double stranded RNA viruses
Group III – Reoviridae
Group IV
single stranded (+) RNA viruses
Group IV – Picornaviridae charactersitics
Group IV – Picornaviridae replication
IRES
Group V
single stranded (-) RNA viruses
Group V – Rhabdoviridae characteristics
Group V – Rhabdoviridae
Group VI
single stranded (+) RNA viruses with DNA intermediate
Group VI – Retroviridae
Group VII
double stranded DNA viruses with RNA intermediate
Group VII – Hepadnaviridae
Last changeda year ago
