Correction to: Nature https://doi.org/10.1038/nature03452 Published online 14 April 2005

It has been brought to our attention that there may have been inadvertently duplicated blank images in the construction of several figures. Actually, these figures, which required removing specific lanes of ChIP or RT-PCR data from gels and insertion into panels, were constructed with the assistance of a graphic artist for aesthetic purposes. At the time of article preparation, we gave a graphic artist raw data for scanning and got back scanned figures for review and proofing, but unfortunately we failed to detect inadvertent duplication of these negative blank data in the figures. Now we provide all of the raw data for these duplicated blank images from the original notebook figures to document the accuracy of the original data. See Supplementary Information below. We believe that the errors in panel insertion did not alter the conclusions of the paper. We deeply regret these mistakes in figure preparation. The affected figure panels are Figures 1a, 2a, 2f, 3c, 3f and 4a. The original article remains unaltered; readers should consult this notice while reviewing the article.

Supplementary information is available in the online version of this Amendment.