Characterization and Promoting Efficacy of the Porcine Endogenous Retrovirus 5′ Untranslated Region

【Objective】The study analyzed the transcriptional regulation of porcine endogenous retrovirus(PERV) 5′ untranslated region(5′UTR).【Method】 A series of functional region deletion of PERV 5′UTR were cloned,including completed 5′UTR,5′UTR lacking of PBS and Leader(5′LTR),5′UTR lacking of U3 region,5′UTR lacking of R region,5′UTR devoid of the U3 repeat box.Scientists then studied the activity of UTRs from replication-competent molecular clones by performing luciferase reporter assays.【Result】The UTR has higher promoter activity than that of LTR.5′UTR lacking the R region showed strong promoter activity,whereas for 5′UTR devoid of the U3 repeat box,the promoter activity was significantly decreased.5′UTR lacking the entire U3 displayed higher promoter activity than that of 5′UTR only lacking the U3 repeat box.【Conclusion】There may have been an interaction of some factors with the R region causing suppressed activity.The U3 repeat box acted as an enhancer;where the downstream sequence of 5′UTR(PBS and Leader) may have had transcription factors’ binding sites regulating this positive effect.The upstream sequences of U3 may have cis-elements that reduce the transcriptional activation of 5′UTR.