Fig. 7. In vitro ubiquitylation of p27 does not require interaction with mNPAP60. Shown are fluorograms of in vitro ubiquitylation reactions using p27 synthesized in a reticulocyte lysate and an S phase extract from HeLa cells. The panel shows time-courses of ubiquitylation reactions using the indicated alleles of p27. Controls established that the bands indicated are generated in a ubiquitin- and ATP-dependent manner (not shown). The * indicates a background band that is present in reactions in the absence of ubiquitin and HeLa extracts.