Skip to content
Learn Motion
ExploreHow it worksMembership
Log in
Learn Motion

How Viruses Enter Cells, Replicate, and Evade Immunity

1Viral Architecture and the Logic of the Life Cycle2Attachment and Entry: Crossing the Membrane3Genome Replication and Gene Expression4Assembly, Egress, and Transmission5Innate Immune Detection of Viral Infection6Adaptive Immunity: Antiviral Antibodies and T Cells7Immune Evasion Strategies8From Mechanism to Intervention: Antivirals and Vaccines
Genome Replication and Gene Expression

DNA Virus Replication: Nuclear Versus Cytoplasmic

3 / 4
Compare the two compartments. On the left, a DNA virus replicates in the nucleus. It uses the host's DNA polymerase to copy its genome and the host's RNA polymerase to make mRNA. This is efficient because the machinery is already there, and it also allows the virus to splice its transcripts. On the right, a poxvirus replicates in the cytoplasm. The host replication machinery is in the nucleus, so the virus must bring or encode its own DNA polymerase and transcription factors. It also packages a DNA-dependent RNA polymerase so it can make mRNA in the cytoplasm. The key difference is dependence on host machinery: nuclear DNA viruses rely on it, cytoplasmic DNA viruses are more self-sufficient. That difference shapes how each virus interacts with the cell cycle and how it responds to drugs that block host DNA replication.
0:00 / 0:00

DNA viruses face a different problem: their genome is DNA, but they must still produce mRNA that host ribosomes can translate. Most DNA viruses replicate in the nucleus because that is where the host's DNA replication and transcription machinery is located. They can use host DNA polymerase and host RNA polymerase, though many also encode their own polymerase or accessory factors to control the process. Nuclear replication allows the virus to take advantage of host enzymes for DNA synthesis and RNA transcription, and it also allows splicing of viral transcripts.

A smaller group of DNA viruses, notably poxviruses, replicate entirely in the cytoplasm. Because the host DNA replication machinery is in the nucleus, these viruses must carry or encode their own DNA polymerase and transcription factors. They also need to solve the problem of synthesizing mRNA in the cytoplasm, which they do by packaging a DNA-dependent RNA polymerase in the virion. The key contrast is that nuclear DNA viruses rely heavily on host machinery, while cytoplasmic DNA viruses are more self-sufficient. This difference affects how the virus interacts with the cell cycle and how it responds to inhibitors of host DNA replication.

Previous3 / 4Next

Learn Motion

Generate a course. Learn it properly.

Operated by Wuhan Daoyin Technology Co., Ltd.

Contact: [email protected]
Privacy PolicyTerms of Service

© 2026 Learn Motion