What is the Difference Between Prophage and Provirus?

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The main difference between a prophage and a provirus lies in the type of host cell they infect and their subsequent behavior within the host. Both prophage and provirus are viral genomes that insert themselves into the host cell's DNA:

  • Prophage: This refers to a bacteriophage DNA that infects bacteria and integrates with their genome. Bacteriophages, or phages, are bacterial viruses. When a prophage integrates into the host genome, it can exist as an extrachromosomal plasmid and can excise itself from the host genome when the host cell is stressed.
  • Provirus: This refers to a viral genome that infects a eukaryotic organism and integrates into its genome. Proviruses can result in latent or productive infections. In a latent infection, the provirus remains transcriptionally silent, while in a productive infection, the provirus is transcribed into messenger RNA, which produces new viruses that can infect other cells via the lytic cycle.

In summary, prophages are bacterial viruses that integrate into bacterial genomes, while proviruses are viral genomes that integrate into eukaryotic genomes.

Comparative Table: Prophage vs Provirus

Here is a table summarizing the differences between prophage and provirus:

Feature Prophage Provirus
Definition Prophage refers to the genome of bacterial viruses integrated into the bacterial genome. Provirus refers to the genome of the virus integrated into the genome of the eukaryotic host cell.
Type of Host Prophage infects bacteria, which are prokaryotic. Provirus infects eukaryotic host cells.
Integration Prophage integrates into the bacterial genome. Provirus integrates into the eukaryotic genome.
Lysogenic Cycle Prophage undergoes the lysogenic cycle, where the viral genome can be excised from the host genome to enter the lytic cycle. Provirus does not excise itself from the host genome when the host cell is stressed.
Replication Prophage replicates as a part of the host genome in the lysogenic cycle. Provirus replicates as a part of the host genome in the lysogenic cycle.

In summary, the main difference between prophage and provirus is the type of host they infect and the integration of their genomes into the host's genome. Prophages are bacterial viruses that integrate into bacterial genomes, while proviruses are viruses that integrate into eukaryotic genomes.