Science 321, 1343–1346 (2008)

The gene Rfv3 has long been known to protect mice against the 'Friend' retrovirus, but its mechanism has proved elusive.

Warner Greene at the University of California, San Francisco, Kim Hasenkrug at Rocky Mountain Laboratories in Hamilton, Montana, and their co-workers show that the effect comes from Rfv3's role in editing the RNA transcript of the gene Apobec3. By intervening in this pathway, they reduced the number of neutralizing antibodies against Friend virus that mice made, and increased their subsequent mortality.

The researchers suggest that this throws light on the importance of the action of the HIV protein Vif on APOBEC3 in humans, which they think accounts for the poor neutralizing antibody responses generally seen in HIV infection.