Li, Y., Li, L., Irvine, K. D. and Baker N. E. Development130,2829-2840.
Several errors in this article were not corrected before going to press.
The name of the second author is Liang Lei.
On p. 2830, two fly strains were incorrectly referenced. The text should read: armlacZ transgenes(Vincent et al., 1994); and md0.5-Lacz (Cooper and Bray, 1999).
On p. 2831, two antibodies were incorrectly referenced. The text should read: guinea pig anti-Senseless(Nolo et al., 2000); and rabbit anti-CM1 (Srinivasan et al., 1998).
We apologise to readers and the authors for these mistakes.