Figure 5

Improved Erk activity reporting with modERK-KTR in Drosophila embryos and larval tissue

(A) Schematic of anteroposterior Torso/ERK signaling during early Drosophila development where signaling is restricted to both poles of the blastoderm (shown by orange gradient), excluding the pole cells (cluster of green cells on the right-hand side). Cells shown with black nuclei have high ERK signaling, whereas those with green nuclei have no ERK signaling.

(B and C) Representative images of the posterior half of transgenic Drosophila embryos maternally expressing the original ERK-KTR (B) or modERK-KTR (C) constructs with a polycistronic H2Av-mCherry tag during cell cycles (cc) 13 and 14. Shown is a single z-slice through the center of the embryo (top) and a magnified view of the regions indicated by white boxes (bottom).

(D and E) Representative images of eye imaginal discs ubiquitously expressing ERK-KTR (D) or modERK-KTR (E) constructs with a polycistronic H2Av-mCherry tag under the control of tub-Gal4. The levels of ERK activity, as read out by ERK-KTR constructs, are here compared with the levels of P-ERK.

(F) Quantification of (D) and (E) comparing P-ERK levels with the read out of ERK-KTR (n = 222 cells from 3 discs) or modERK-KTR (n = 293 cells from 3 discs) constructs and fitted with a simple linear regression.

See also Figures S3 and S4.