It has recently been brought to our attention that some of the lanes in the reverse-transcriptase-mediated polymerase chain reaction (RT–PCR) analyses of this Letter appear to be duplicated. Specifically, two β-actin bands in Fig. 1c, lanes 1, 4 and 6 of the αMHC bands and lanes 1 and 6 of the GATA4 bands in Fig. 3e, lane 1 of the Nkx2.5 band and lane 3 of the GATA4 band in Supplementary Fig. 3e, and lane 1 of the Nkx2.5 band and lane 1 of the β-actin band in Supplementary Fig. 3f might be duplicated. Lane 2 of the GATA4 band in Supplementary Fig. 3c might be ‘pasted in’. Because the original raw data could not be located, we were unable to verify definitively whether the data in the original figures are correct or whether some of the lanes were indeed inadvertently duplicated. We therefore repeated the RT–PCR experiments shown in these figures. There is one difference in the experimental procedures between the original work and the repeated experiments. In the original work, knockdown of insulin-like growth-factor-binding protein 4 (IGFBP-4) in P19CL6 and embryonic stem (ES) cells was achieved by establishing stable cell lines that constitutively express IGFBP-4 small interfering RNAs (BP4-1 and BP4-2 in Fig. 3e and Supplementary Fig. 3e). In the repeated experiments, knockdown of IGFBP-4 was done by transient transfection of IGFBP-4 siRNAs. Figure 1 of this Corrigendum shows the corrected right-hand panels of the original Figs 1c and 3e. The Supplementary Information of this Corrigendum shows the corrected Supplementary Fig. 3c, e and f of the original Letter (in which the RT–PCR panels represent new and independent experiments); it also contains the raw data for all the corrected figures. Repeated experiments show that the results are reproducible and essentially the same as those of the original Letter. We thank Seitaro Nomura from the University of Tokyo, who generated data for the corrigendum. We apologize for any confusion these possible errors may have caused. The corrections described here do not alter the overall conclusion that IGFBP-4 promotes cardiogenesis by inhibiting canonical Wnt signalling.
- Supplementary Information (641 KB)
This file contains corrected Supplementary Figure 3 and the raw data for Figures 1c, 3e in the main paper and Supplementary Figure 3c, e and f (see the associated corrigendum for details).