VOLUME 284 (2009) PAGES 15676–15684
The authors were recently made aware of an accidental duplication of two panels in Fig. 2C: day 4 and day 7 mock samples. Using the original Tiff images of each panel, a corrected Fig. 2C has been assembled. An Inquiry Committee at the University of Massachusetts Medical School determined that the error had no adverse effects on the conclusions reported in the publication, as multiple experimental approaches were presented that validated the findings. This correction does not affect the results or conclusions of this work. The authors apologize for this error.
Figure 2C.
