 Expression extends anteriorly and ends sharply at the ZLI, with high expression along the line where "Shh" is expressed.Before the ZLI is formed, "OTX2]" is expressed ubiquitously throughout the forebrain, and begins to recede to the position of the putative ZLI.Experiments where "OTX2]" expression was repressed showed no dorsal movement of "Shh" expression and no ZLI formation.