Abstract: Objective To explore biological function of gene family Pax7,its interaction with gene coding protein Ubc9,and the relationship between Pax7 and small ubiquitin-related modifier(SUMO).Methods Yeast two-hybrid was applied to screen out Ubc9 interacted with Pax7.The interaction between Pax7 and Ubc9 in vitro was confirmed with glutathione-S-transferase(GST) pull-down.Western blot was used to detect the SUMOylation of Pax7.The interaction between Pax7 and SUMO was demonstrated with co-immunoprecipitation(Co-IP).Results There was an interaction between Pax7 and Ubc9 in yeast.Pax7 can bind to Ubc9 specially in vitro.Pax7 could be SUMOylated in the presence of Ubc9 and it also could interact with SUMO.Conclusion The results demonstrate that Pax7 interacts with Ubc9,and the interaction leads to the SUMOylation of Pax7.