Editing HIV to death

Interferon (IFN)-α gives macrophages the upper hand against HIV, according to a study on page 41. Peng and colleagues show that the cytokine IFN-α enhances the expression of the RNA-editing enzyme APOBEC3G, which mutates HIV DNA, thus triggering its degradation.

APOBEC3G is a close relative of the B cell–specific protein AID (activation-induced cytidine deaminase), which mutates immunoglobulin DNA to generate high affinity antibodies. APOBEC3G—which may have evolved as a regulator of endogenous retroviruses—recently emerged as an inhibitor of HIV replication in T cells, owing to its propensity to mutate retrotranscribed viral DNA. But HIV effectively counters this defense with the Vif protein, which binds to APOBEC3G and targets it for proteasomal degradation.

Boosting cellular levels of APOBEC3G might be an effective way to combat the destructive effects...