Viral replication

Viral replication is the formation of biological viruses during the infection process in the target host cells.

The host cell must provide the energy and synthetic machinery and the low-molecular-weight precursors for the synthesis of viral proteins and nucleic acids.

Receptor-mediated endocytosis occurs when a molecule (in this case a virus) binds to receptor on the membrane of the cell.

[3] Viruses enter host cells using a variety of mechanisms, including the endocytic and non-endocytic routes.

[6] Evidence shows that viruses utilize ion channels on the host cells during viral entry.

[7] This forms a pore in the host membrane, and after entry, the virion becomes uncoated, and its genomic material is then transferred into the cytoplasm.

[10] Endocytic routes: the process by which an intracellular vesicle is formed by membrane invagination, which results in the engulfment of extracellular and membrane-bound components, in this context, a virus.

Uncoating is defined by the removal of the virion's protein "coat" and the release of its genetic material.

Some RNA viruses such as Rhinoviruses use the low pH in a host cell's endosomes to activate their uncoating mechanism.

Many DNA viruses travel to the host cells nucleus and release their genetic material through nuclear pores.

Assembly is when the newly manufactured viral proteins and genomes are gathered and put together to form immature viruses.

Assembly can occur in the plasma membrane, cytosol, nucleus, golgi apparatus, and other locations within the host cell.

[3] The final step in viral replication is release, which is when the newly assembled and mature viruses leave the host cell.

There are seven different replication strategies based on this system (Baltimore Class I, II, III, IV, V, VI, VII).

[18] RNA viruses present a therapeutic double-edged sword: RNA viruses can withstand the challenge of antiviral drugs, cause epidemics, and infect multiple host species due to their mutagenic nature, making them difficult to treat.

Replication is monocistronic and includes individual, segmented genomes, meaning that each of the genes codes for only one protein, unlike other viruses, which exhibit more complex translation.

These can be divided into two groups, both of which replicate in the cytoplasm: Examples of this class include the families Coronaviridae, Flaviviridae, and Picornaviridae.

This small group of viruses, exemplified by the Hepatitis B virus, have a double-stranded, gapped genome that is subsequently filled in to form a covalently closed circle (cccDNA) that serves as a template for production of viral mRNAs and a subgenomic RNA.

The pregenome RNA serves as template for the viral reverse transcriptase and for production of the DNA genome.