APPLIED BIOLOGICAL SCIENCES, ENGINEERING Correction for “A modular and extensible RNA-based gene-regulatory platform for engineering cellular function,” by Maung Nyan Win and Christina D. Smolke, which appeared in issue 36, September 4, 2007, of Proc Natl Acad Sci USA (104:14283–14288; first published August 20, 2007; 10.1073/pnas.0703961104).
The authors note that on page 14284, right column, starting on line 28 of the second full paragraph, “An ≈25-fold increase in target expression levels at 5 mM theophylline, relative to those in the absence of effector, was observed in L2bulge1 (Fig. 2C and SI Fig. 8). In contrast, an ≈18-fold reduction in expression levels at 5 mM theophylline, relative to those in the absence of effector, was observed in L2bulgeOff1 (Fig. 2D and SI Fig. 8)” appeared incorrectly. The text should instead read: “An increase in target expression levels (induction in fold ≈25) at 5 mM theophylline, relative to those in the absence of effector, was observed in L2bulge1 (Fig. 2C and SI Fig. 8). In contrast, a reduction in expression levels (repression in fold ≈18) at 5 mM theophylline, relative to those in the absence of effector, was observed in L2bulgeOff1 (Fig. 2D and SI Fig. 8).” In addition, the authors note that all switch dynamic range data (Figs. 2–6) reported as induction or repression or normalized gene expression in fold reflect the definitions described in SI Text (Materials and Methods). These errors do not affect the conclusions of the article.