Figure 4. Atonal regulates RhoBAD activity.

A-C. Lateral views of stage 11 RhoBAD-lacZ Drosophila embryos immunostained for β-gal (green) and Salm (red). Close-ups of one thoracic and three abdominal segments (A1 labeled) are shown at right. Note that wild type embryos (A, A’) contain abdominal C1 SOP cells (marked by β-gal) surrounded by whorls of oenocytes (high Salm). The thoracic C1 SOP cells show weak β-gal without adjacent whorls of Salm-positive cells (arrow). In contrast, both ato¹ (B, B’) and sens^E2 (C, C’) mutant embryos have fewer abdominal segments that express β-gal, and those segments that do are surrounded by fewer oenocytes (arrow) than wild type embryos. D-F. Lateral views of RhoBAD-lacZ stage 16 embryos immunostained for β-gal (green) and Salm (red). Close up views of four abdominal segments is shown at right. Wild type embryos (D, D’) have RhoBAD-lacZ activity in the abdominal C1 SOP lineage with clusters of Salm-positive oenoyctes in close proximity, whereas both ato¹ (E, E’) and sens^E2 (F, F’) mutant embryos show a loss of both β-gal and Salm-positive cells in many abdominal segments. Close-up views show segments completely lacking β-gal and oenocytes (arrow), whereas other segments express weak β-gal and have few oenocytes. G. Quantification of oenocyte (Oe) numbers in wild type, ato¹ and sens^E2 embryos. * denotes p-value < 0.001.