Retooling Degradation Factories

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Science  13 May 2005:
Vol. 308, Issue 5724, pp. 927
DOI: 10.1126/science.308.5724.927b

After breaching the outer defenses and establishing themselves inside a eukaryotic cell, viruses subvert existing cellular machinery in order to produce their progeny. When human cells are infected by poliovirus, new viruses are manufactured on cytoplasmic vesicles that are bounded by a double membrane. Jackson et al.examined the origin of these virus factories and found that they appear to be derived from autophagosomes, cellular compartments that ordinarily are used in the disposal of defunct organelles. It seems that after cellular invasion, the incoming virus becomes associated with membranes that mature into autophagosomes. Stimulation of autophagy in infected cells actually increased poliovirus yield, whereas inhibition reduced it. Although autophagy is known to be important in the cellular clearance of some microbes (such as Mycobacterium tuberculosis), for poliovirus and for related rhinoviruses, these destructive organelles are actually exploited to increase the efficiency of viral replication. — SMH

PLoS Biol. 3, e156 (2005).

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