Vol. 208, No. 11, September 26, 2011. Pages 2193–2199.

The authors regret that they included incorrect immunohistochemistry images in the original Fig. 3 B. The original Fig. 3 legend also lacked information defining the stains represented by red and green colors in Fig. 3 B. These errors have been corrected in the html and pdf versions of this paper. The corrected figure and legend are below.