Cover image

Cover Growth arrest-specific-1 (Gas1) is a cell surface-associated, hedgehog-binding protein that promotes Sonic hedgehog (Shh) signaling in multiple tissues, including the developing spinal cord. Shown here is an immunofluorescence analysis of a chick neural tube following electroporation with Gas1 (green). Examination of the ventral progenitor cell markers Nkx2.2 (red) and Olig2 (blue) reveals that Gas1 promotes the ectopic expression of these markers in a cell-autonomous manner. These data uncover a crucial role for Gas1 in the specification of Shh-dependent ventral cell identities during neural tube patterning. (For details, see Allen et al., p. 1244, and related paper by Martinelli and Fan, p. 1231.)