Fig. 1. Ectopic tsh can induce HTH and suppress eye development. (a) dpp>tsh, which drives expression of tsh along the lateral and posterior margin of the eye disc, caused splitting of the endogenous eye (arrow indicates the ventral eye) and induced an ectopic eye at the base of the antenna (arrowhead) in the pharate adult. All eye discs in this and subsequent figures are oriented anterior towards the left and dorsal towards the top. (b,c) dpp>tsh eye disc (photoreceptors labeled by ELAV, blue; HTH, red). Eye disc (E) is highly reduced (arrow) relative to the antenna disc (AN). (d) dpp>2Xtsh caused suppression of the ventral eye. (e) ey>tsh caused complete loss of eye (ELAV, blue) and ectopic induction of HTH (red). The size of the eye disc is extremely reduced. (f) ey>tsh adult showed complete loss of eye. (g) dpp>tsh in an hth^1422-4/+ background resulted in pharate adult with rescue of the dpp>tsh split-eye phenotype and (h) dpp>tsh+hth caused complete eye loss.