Contents

17 September 1993
Vol 261, Issue 5128

About The Cover

Confocal immunofluorescent detection of wingless protein (green), engrailed protein (blue), and enhancer trap 5953 (red) in a reiterated segment of embryonic Drosophila neuroectoderm (ventral midline, center; anterior, top). The wingless protein nonautonomously activates 5953 expression, maintains expression of the engrailed protein, and controls the formation and specification of central nervous system precursors. See page 1594. [Photo: Chris Q. Doe]