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Fig. 3 | BMC Biology

Fig. 3

From: Autophagy-independent function of Atg1 for apoptosis-induced compensatory proliferation

Fig. 3

dAtg1 acts genetically downstream of or in parallel to JNK and upstream of Wg expression. Late third instar eye (af’) or wing (gi’) discs, anterior is to the left. The cleaved Caspase-3 (cCasp3) labeling (green in ai) indicates activity of Dronc in p35-expressing tissues. White dotted lines in (af’) indicate the anterior portion of the eye discs which expresses ey-Gal4. ELAV labels photoreceptor neurons (blue in af) and is used to mark the posterior differentiating eye field. (ab’) In ey > p35 control discs, puc-lacZ expression (β-Gal; red in a, grey in a’) as a marker of JNK/Bsk activity is low (a’, arrow) in the anterior portion of the eye discs. Expression of Wg (red in b, grey in b’) is restricted to dorsal and ventral edges of the eye discs. Dronc activity indicated by cCasp3 labeling is low. (cd’) In ey > hid-p35 discs, Dronc activity (cCasp3 labeling) is strongly induced in undead anterior tissue (c, d). The anterior portion of the discs between the white dotted lines is significantly expanded and displaces the eye field in the posterior portion of the discs (ELAV). Compared to the ey > p35 control discs (a’, b’), in the overgrown anterior eye portion, JNK activity (c’, arrows) and expression of Wg (d’, arrows) are strongly induced. (ef’) Expression of dAtg1 RNAi suppresses hyperplastic overgrowth in about 80 % of the ey > hid-p35-dAtg1 RNAi discs (n > 60) indicated by the normalized ELAV pattern. This ratio corresponds to the suppression of the adult overgrowth phenotype (Fig. 1i). However, puc-lacZ expression and cCasp3 labeling are not suppressed by dAtg1 RNAi (e’, arrows) in contrast to ectopic Wg expression, which is blocked (f’) in the anterior portion of the eye discs. (gi’) Compared to the control wing discs where p35 is expressed in the pouch area under the control of nub-Gal4 (nub > p35; g, g’), in nub > hid-p35 discs, co-expression of hid and p35 induces tissue overgrowth, increased cCasp3 labeling, and ectopic Wg expression (h, h’; arrows). Similar to eye discs, expression of dAtg1 RNAi largely blocks tissue overgrowth and ectopic Wg, but not the cCasp3 labeling (i, i’). A low level of ectopic Wg remains in nub > hid-p35-dAtg1 RNAi discs (i’, arrow). (j, k) Quantification of cCasp3 labeling intensity in eye and wing discs (mean ± SE). dAtg1 RNAi has no obvious effects on the cCasp3 labeling induced by expression of hid and p35 in both eye (j) and wing (k) discs

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