Fig. 1. Mapping of the col DA3 muscle CRM in Drosophila. (A). Schematic representation of the col genomic region. Coding exons and the 5' and 3' untranslated regions are indicated by black and white boxes, respectively. The positions of the immediately upstream and downstream predicted genes (http://flybase.bio.indiana.edu/), CG10200 and BEAF-32, are indicated by grey boxes and their direction of transcription by arrows. The extent of col upstream region present in each lacZ reporter gene, P9cl to P0.9cl is indicated by a black line. (B) Diagrammatic, colour-coded representation of the different col expression sites in stage 11 and 14 embryos. (C) In situ hybridisation showing expression of P2.6cl, P2.3cl and P1.6cl, compared to endogenous col, at embryonic stages 6, 11, 12 and 14. (D) Close-up view of the DA3 promuscular cluster and progenitor in the T2 and T3 segments of a P9cl embryo at stage 11, stained for Col (green) and β-gal (red). Unlike Col, lacZ expression is restricted to the progenitor cell. (E) Schematic representation of the modular organisation of the col cis-regulatory region, underlining the position of the DA3 muscle CRM.