Figure 6. Fate-specification defects suggest different requirements for Yan polymerization and repression in R7 versus R3/R4 photoreceptors.
(A–E) Adult eye images of indicated genotypes, showing progressive roughening of the eye field for the SuperYan alleles and monomeric Yan V105R. (F) Quantification of sectioning. All genotypes were significantly different from one another, as confirmed by paired Chi-square tests, p<0.001. (G–J) Histological sections of yanSY3–5 and yanV105R. Green arrows indicate extra outer photoreceptors, yellow arrows indicate extra inner photoreceptors; examples shown in (I). (K–M) The expression of Spalt-major (Salm), a marker of R3/4 cell fate, shows increased numbers of R3/4 cells. (N–P) Expressions of Prospero (Pros), a marker of R7 cell fate, shows no expansion of the R7 lineage in yanSY5 discs. White arrows mark the position of the morphogenetic furrow; green and yellow arrows mark examples of extra Salm-positive and Pros-positive cells, respectively. Scale bars represent five microns.