Fig. 4. Ebony protein is expressed widely and does not correlate with a single pigment. (A) Immunohistochemical staining of e^AFA with the Ebony antibody does not detect any staining at approximately 72 hours APF. In pharate adults, a weak signal is produced in epidermal cells (data not shown). (B) From approximately 72 to 90 hours APF, Ebony protein (green) is expressed in cells associated with mechanosensory bristles (arrow), but not in epidermal cells (arrowhead). This expression may not function in pigmentation because e mutants have wild-type bristle color. (C) Beginning at approximately 90 hours APF, low levels of Ebony protein (green) are present in all epidermal cells of each abdominal segment. Bracket indicates the future location of the pigment stripe and staining of cells near the top of the panel is in a different focal plane. (D) In the thorax, highest levels of Ebony expression are in epidermal cells that produce the ‘trident’ in e mutants (arrow). The strong staining seen near the top of the panel is background signal from underlying tissues.