Final answer:
Adenovirus late gene expression is turned on after the initial phase of the viral lifecycle, usually following viral DNA replication. It is regulated by viral proteins that can include E1A and E2 and is critical for virus assembly. Late gene expression is necessary for the production of structural proteins for new virions.
Step-by-step explanation:
The expression of late genes in adenovirus is a highly regulated process that is triggered after the early phase of viral gene expression. Late gene expression is essential for the production of structural proteins necessary for virus assembly.
It typically begins after the virus has replicated its DNA and is ready to assemble new virions. This transition from early to late gene expression is controlled by various viral proteins that accumulate during the infection, which can include regulatory proteins named E1A and E2, among others.
The late genes are typically expressed from major late promoters (MLPs), and their expression can be affected by cellular factors and the viral DNA replication status.
Regarding the broader context, viruses like adenovirus follow a sequence of infection events that are well-orchestrated.
Some viruses carry genes that can lead to tumor formation either quickly (acutely-transforming) or slowly (slowly-transforming), depending on whether they carry a viral oncogene or cause overexpression of host proto-oncogenes.
Understanding viral mechanisms such as these, including the response to interferons and how viruses can disrupt or utilize host cell machinery, is critical for developing antiviral therapies and gene therapy strategies.