Fig. 9.

Model for the role GAPDH in stimulation of tombusvirus positive-strand synthesis. GAPDH likely binds to p92 and recruit p92 to the (−)RNA intermediate within the viral replicase complex through binding to an AU-pentamer sequence as shown. Note that the reverse order of binding GAPDH to the (−)RNA first and then to p92 is also equally possible. This is followed by the GAPDH-mediated proper positioning of p92 over the negative-strand template, thus facilitating positive-strand synthesis. The GAPDH-driven binding/positioning of p92 onto the (−)RNA template could occur many times, leading to the production of abundant positive-strand progeny and resulting in asymmetric RNA synthesis.