5256 Nucleic Acids Research, 2010, Vol. 38, No. 15 Figure 13. Native and modiﬁed duplexes have the same eﬀect on antisense transcript levels. (A) Treatment of T47D cells with PR-9 and modiﬁed duplexes leads to a signiﬁcant downregulation of both PR mRNA (left) and the promoter-associated antisense transcript (right). (B) Treatment of MCF7 cells with PR-11 and modiﬁed duplexes leads to a signiﬁcant upregulation of PR mRNA (left) but no signiﬁcant change in levels of the promoter-associated antisense transcript (right). *P < 0.05, **P < 0.01, ***P < 0.005. Figure 14. Inactive modiﬁed duplexes do not compete for target sites. Western analysis showing no competition between native agRNAs and inactive modiﬁed duplexes applied to cells in two transfections 4 days apart. (A) Native PR-9 silences gene expression equally eﬀectively whether it is transfected before or after an inactive chemically modiﬁed duplex (or negative control). (B) Native PR-11 activates gene expression equally eﬀectively whether it is transfected before or after an inactive chemically modiﬁed duplex.