Replicative cycles of DNA (A) and RNA (B) viruses. The replicative cycles of herpesvirus (A) and influenza (B) are examples of DNA-encoded and RNAencoded viruses, respectively. Sites of action of antiviral agents also are shown. cDNA, complementary DNA; cRNA, complementary RNA; DNAp, DNA
polymerase; mRNA, messenger RNA; RNAp, RNA polymerase; vRNA, viral RNA. The symbol indicates a block to virus growth. A. Replicative cycles of
herpes simplex virus, a DNA virus, and the probable sites of action of antiviral agents. Herpesvirus replication is a regulated multistep process. After
infection, a small number of immediate-early genes are transcribed; these genes encode proteins that regulate their own synthesis and are responsible for
synthesis of early genes involved in genome replication, such as thymidine kinases, DNA polymerases, etc. After DNA replication, the bulk of the
Source: Antiviral Agents (Nonretroviral), Goodman and Gilman's Manual of Pharmacology and Therapeutics, 2e
herpesvirus genes (called late genes) are expressed and encode proteins that either are incorporated into or aid in the assembly of progeny virions. B.
Citation:
Hilal-Dandan
R, Brunton
and
Gilman's
Manualagents.
of Pharmacology
and Therapeutics,
2e;an2016
Available
at: cell. The M2
Replicative cycles
of influenza,
an RNA
virus, LL.
andGoodman
the loci for
effects
of antiviral
The mammalian
cell shown is
airway
epithelial
http://mhmedical.com/
Accessed:
July
28,
2017
protein of influenza virus allows an influx of hydrogen ions into the virion interior, which in turn promotes dissociation of the RNP (ribonuclear protein)
Copyright
© 2017
McGraw-Hill
Education.Influenza
All rights virus
reserved
segments and
release into
the cytoplasm
(uncoating).
mRNA synthesis requires a primer cleared from cellular mRNA and used by the viral
RNAp complex. The neuraminidase inhibitors zanamivir and oseltamivir specifically inhibit release of progeny virus.