Fig. 1.

Pros cell type-specific expression is regulated post-transcriptionally. (A) Illustration of smFISH probe positions on the pros mRNA transcript isoforms. (B) Third instar larval brains stained for smFISH against pros exon, with IF against Elav and Pros. pros mRNA is upregulated in post-mitotic neurons (marked with Elav), and this correlates with upregulated Pros protein. (C) smFISH against the pros intron and pros exon (probe positions shown in A) together with IF against Pros protein, shows that pros is transcribed in all cells of the Type I NB lineage, even in NBs where there are low levels of Pros protein and pros mRNA. Scale bars: 10 µm. NB, white dashed outline; GMC, pink outline.