Filling a GAP(DH) in asymmetric viral RNA synthesis.

Host proteins, such as RNA-binding proteins, are involved in most steps of replication by positive-strand RNA viruses, including Tomato bushy stunt virus (TBSV). In this issue of Cell Host & Microbe, Wang and Nagy report that efficient replication of TBSV requires GAPDH, a host protein with glycolytic, RNA-binding, and other functions. GAPDH binds TBSV (-)RNA and promotes the normal excess of (+)RNA over (-)RNA products, possibly by selectively retaining (-)RNA templates for copying.