FIGURE 6.

Model for dsRNA degradation by the hSUV3 hPNPase complex. The assembly of the heteropentameric complex takes place first (Step 1), followed by loading of the complex onto the single-stranded portion of the dsRNA substrate (Step 2). The complex then moves along the ssRNA track toward the 5′ with hSUV3 leading hPNPase. When a duplex region is reached, hSUV3 unwinds the double strand in the presence of ATP to allow the complex to degrade the exposed single strand exoribonucleolytically (Steps 3 and 4) until the RNA is degraded to roughly 6 nucleotides long (Step 5).