Off-target effects dominate a large-scale RNAi screen for modulators of the TGF-β pathway and reveal microRNA regulation of TGFBR2

Table 1 Repression of TGFBR1 and TGFBR2 mRNAs by the 193 tested screen siRNA^a hits^b.

Off-target mRNAs affected	Number of siRNAs
TGFBR1 only	21^c
TGFBR2 only	109
Both TGFBR1 and TGFBR2	42
No off-target effect (false positives)	21

^asiRNA = small interfering RNA.
^bScreen hits were grouped by their effects on mRNA levels of TGFBR1 and TGFBR2, as determined by branched DNA assay (most siRNA) or quantitative (q)PCR (some siRNA).
^cFor the 21 siRNAs without off-target effects, the effects on TGF-β signaling were not verifiable by phospho-SMAD2 western blots or by qPCR of characteristic TGF-β target gene mRNAs (false positives) (see Additional File 2 Table S3 for detailed expression data).