Figure 3.

Down-regulation of Ato by the MAPK signaling. The hs-rho eye disc was heat-treated for 30 min (A) showing increase of MAPK activation, or for 1 hr preceded by a 2-hr rest showing Ato repression in the stripe (B), by a 4-hr rest showing repression in proneural clusters (C), or by a 6-hr rest showing repression in R8 precursors (D). (E and F) Multiple heat pulses (see Materials and Methods) result in great reduction of Ato-positive cells (E), and Boss and Elav (F) staining. The double arrows indicate the missing rows of Elav and Boss expression (F). The hs-aos disc was heat-treated for 1 hr, showing repression of dp-ERK (G) and activation of Ato (H). Prolonged heat treatment did not affect R8 specification as shown in I. (A–I) Ato is red, dp-ERK is green, Elav is purple, and Boss is blue.