Beating intruders at their own game

Bacteriophages (or phages for short) are bacteria-infecting viruses. Some phages can integrate into bacterial genomes where they lie dormant (in a prophage state) as long as host conditions remain stable. Upon detection of bacterial damage, prophages are released from the host genome and enter the lytic cycle, destroying the host cell.

Recently, bacterial proteins with substantial structural similarity to virus capsid proteins were shown to assemble into large polyhedral shells capable of sequestering enzymes involved in oxidative-stress response (Sutter 2008, News & Views in Heinhorst 2008). Many other virus-like bacterial proteins exist (see e.g. 3bjq, 3bqw) that could carry out similar functions.

Since the products of oxidative-stress, such as hydrogen peroxide, can induce DNA damage and the SOS response that triggers prophage release (Bol 1990), isolation of cytotoxic compounds by means of such bacterial nanocompartments, termed encapsulins, could provide a means for virus-infected bacteria to avoid lysis.

Subverting a viral intruder by means its own tools – an example of poetic justice?

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