Supplemental Data. Supp Figure 1: Expression of So-Gal4 and Sev-Gal4

SUPPLEMENTAL DATA. Supp Figure 1: Expression of so-Gal4 and sev-Gal4.

Lateral view on the head region of an so-Gal4, UAS-CD8::GFP labeled with anti-GFP

(green) and anti-FasII (red) at embryonic stage mid 10 (A) and stage 15 (C). GFP expression is detected in the optic lobe primordium (arrow) including presumptive larval

PR precursors (A) and immature PRs (C). (B) Lateral and (D) dorsal view on the head region of an sev-Gal4, UAS-CD8::GFP labeled with anti-GFP (green) and anti-FasII

(red) at embryonic stage mid 12 (B) and stage 15 (D). GFP expression is detected in immature larval PRs from the detachment of the optic lobe (arrow in B) and immature

PRs at sage 15.

Supplemental Figure 2: Expression of the Ets transcription factors Yan and Pnt during larval eye development

(A, E) Lateral view of a so-Gal4/UAS-H2B-YFP stage 11 embryonic head region stained with anti-GFP (green) and anti-Yan (red) antibodies. The region giving rise to larval PRs

(ventral/lateral tip) strongly expresses Yan (compare arrows in A and E. E shows only anti-Yan). (B, F) Dorsal view of high magnification of so-Gal4/UAS-H2B-YFP stage 15

BO labeled with anti-GFP (green), anti-Yan (red) and anti-Elav (blue) antibodies. No

Yan expression can be detected in immature larval PRs during this stage (compare arrows in B and F. F shows only anti-Yan). (C, G) Lateral view of a so-Gal4/UAS-H2B-YFP stage 11/12 embryonic head region stained with anti-GFP (green) and anti- Pnt (red) antibodies. The region giving rise to larval PRs (ventral/lateral tip) expresses Pnt

(compare arrows in C and G. G shows only anti-Pnt). (D, H) Dorsal view of high magnification of so-Gal4/UAS-H2B-YFP stage 15 BO labeled with anti-GFP (green), anti-Pnt (red) and anti-Elav (blue) antibodies. No Pnt expression can be detected in immature larval PRs during this stage (compare arrows in D and H. H shows only anti-