tokens: Analysis of the E2F1 gene promoter showed that the -146 to -54 region was required for E2 responsiveness in transient transfection assays , and subsequent deletion / mutation analysis showed that a single upstream GC rich and two downstream CCAAT binding sites were required for transactivation by E2 .
folded_tokens: analysis of the e2f1 gene promoter show that the -146 to -54 region be require for e2 responsiveness in transient transfection assay , and subsequent deletion / mutation analysis show that a single upstream gc rich and two downstream ccaat binding site be require for transactivation by e2 .