Fig 6. An Asp at the MAPK site engenders M8 activity at stage-1 of the MF.

(A-C) Scanning EM of adult eye at 200x magnification. The MAPK mimic M8-S151D (A) and the dual-kinase mimic M8-S151D+S159D (B) elicit a reduced eye, whereas a WT eye is evidenced upon expression of M8-S151A+S159D, a variant refractory to MAPK (C). (A’-C’) 1000x magnification of the eyes in panels A-C. Note that M8 variants with an Asp at the MAPK site elicit the specification of extra IOBs (A’, B’), whereas such defects are infrequently seen upon expression of M8-S151A+S159D (C’). (D) For each genotype, the number of images analyzed for eye size (ommatidial/facet counts) is indicated. Genotypes shown in panels A-C were compared to control (hH¹⁰Gal4/+), and ** denotes P-value < 0.001.