Analysis of emc function.

(A–D) emcpel mutant phenotype. (A, B) Expression of sca and Hnt in a heterozygous control disc. (C, D) Expression of the marker in an emcpel homozygous disc. The expression of sca has expanded and many more cells express Hnt in the mutant disc, indicating an expansion of the proneural band and formation of more SOPs at ectopic positions. (E–P) Clonal analysis of emc. Clones are labelled by the loss of GFP and outlined in several panels. (E–J) hsFlp induced emc null mutant clones. (K–M) Null mutant clones induced by UAS Flp driven by ptcGal4. All cells of the clones express elevated levels of sca (arrows) and several also Hnt (arrowheads). Note, that elevated sca expression and SOP formation is also observed in the posterior compartment (H–I, arrows, arrowheads in J). (N–P) Ectopic sca expression is already observed in early third larval instar discs long before the normal PNCs appear (arrows and arrowheads). White scale bar 50µm.