CUG and CAG Repeat RNA Pathogenesis in Drosophila Figure 5. Ubiquitous CUG and CAG RNA repeat expression leads to distinct localisation in muscle nuclei. Images from cryosections hybridised with fluorescent probes to detect repeat RNA. Images are representative of observations from multiple animals and independent transgenic lines for each repeat. A, Schematic of the repeat expression construct, indicating the location of the repeat and probe. B-E, Repeat transcripts detected with a complementary repeat probe. B, Progeny carrying the da-GAL4 driver alone show no signal in the nucleus. C, Expression of 4xrCUG,100 [line 2] leads to multiple foci throughout the nucleus. D, E, Expression of 4xrCAG,100 [line 1], or 4xrCAA,100 [line 1] leads to between one and four sites of RNA concentration (arrowheads). F, Schematic of the construct giving repeat expression within the context of the GFP transcript, in this case RNA is detected using a probe against the GFP sequence. G-K, Repeat RNA localisation when expressed within a GFP transcript. G, No signal is observed using the GFP complementary probe against control EV progeny. H, 4xrCUG,100-GFP expression leads to a similar pattern of PLoS ONE | www.plosone.org 9 June 2012 | Volume 7 | Issue 6 | e38516