Viral Genetics, Transduction, and Retroviruses (2B) Practice Test

A retrovirus is engineered with a mutated integrase that can bind viral DNA but cannot catalyze strand transfer into host DNA. In infected cells, reverse-transcribed viral DNA is detected, and viral proteins are produced for a short period, but the signal rapidly declines over subsequent cell divisions. No integrated proviral DNA is detected.

Based on the vignette, which conclusion is most consistent with retroviral integration?

A research team tracks the replication of an enveloped retrovirus in permissive mammalian cells. They observe: (1) early synthesis of viral DNA from an RNA template, (2) later detection of viral DNA in the nucleus, (3) persistent viral DNA integrated into host chromosomes, and (4) production of viral proteins followed by release of new enveloped virions from the plasma membrane. A drug blocks the viral protease, and virions are still released but are poorly infectious.

Which outcome would be expected during the viral replication cycle described when the protease is inhibited?