Nucleic Acids Res. 2012; 40, 3329–3347. doi:10.1093/nar/gkr1232
The authors wish to apologize for errors in Figures 4A and 6B, where the panels were misaligned with the headings. The corrected Figures 4 and 6 appear in full below.
Figure 4.
Figure 6.

These corrections do not influence the validity of the results and the conclusions of this article.

