Chika Yokota, Matt Kofron, Mike Zuck, Douglas W. Houston, Harry Isaacs,Makoto Asashima, Chris C. Wylie and Janet Heasman Development130, 2199-2212.

On p. 2200, the sequence of Xnr3 morpholino oligo is incorrect. The correct sequence is 5′TCTCTGGGTAGATTTGTGGTGACTC 3′.

The authors apologise to readers for this mistake.