Ubiquitous CUG and CAG RNA repeat expression leads to distinct localisation in muscle nuclei.

<p>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. <b>A</b>, Schematic of the repeat expression construct, indicating the location of the repeat and probe. <b>B-E</b>, Repeat transcripts detected with a complementary repeat probe. <b>B</b>, Progeny carrying the <i>da-GAL4</i> driver alone show no signal in the nucleus. <b>C</b>, Expression of <i>4xrCUG_∼100 [line 2]</i> leads to multiple foci throughout the nucleus. <b>D, E</b>, Expression of <i>4xrCAG_∼100 [line 1]</i>, or <i>4xrCAA_∼100 [line 1]</i> leads to between one and four sites of RNA concentration (arrowheads). <b>F</b>, 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. <b>G-K</b>, Repeat RNA localisation when expressed within a GFP transcript. <b>G</b>, No signal is observed using the GFP complementary probe against control EV progeny. <b>H</b>, <i>4xrCUG_∼100-GFP</i> expression leads to a similar pattern of foci as in <b>C</b>. <b>I, J</b>, Expression of 4x<i>rCAG_∼100-GFP</i> or <i>4xrCAA_∼100-GFP</i> leads to a similar pattern as in <b>D</b> and <b>E</b>. <b>K</b>, Expression of a single copy of GFP, not containing a repeat, leads to the formation of a single similar site of RNA concentration.</p

Reducing Mbl levels does not enhance the tergite phenotype.

<p><b>A-D</b>, Proportion of progeny within each phenotype category when repeat expression is driven by <i>da-GAL4</i> alone (left column), or in the presence of the <i>mbl^E27</i> mutant allele such that Mbl levels are reduced (right column). <b>A</b>, Wild-type control, <b>B</b>, <i>4xrCAA_∼100 [line 1]</i>, <b>C</b>, <i>4xrCUG_∼100 [line 1]</i>, <b>D</b>, <i>4xrCAG_∼100 [line 2]</i>. <b>E, F</b>, Total proportion for each genotype that shows any phenotype (‘any phenotype’ - category 2, 3 and 4) and the proportion with a strong phenotype (‘strong phenotype’ – category 3 and 4). <b>E</b>, <i>4xrCUG_∼100 [line 1]</i> shows a reduction in the proportion with any phenotype, but no change in the proportion with a strong phenotype with reduced Mbl levels. <b>F</b>, No significant effect was observed with <i>4xrCAG_∼100 [line 2]</i>. Comparisons were made using Fisher’s exact test, with significant results indicated above the proportion, where *p<0.05.</p

Reduced Dicer-1 processing can have opposing effects on CUG or CAG RNA-mediated tergite phenotypes.

<p><b>A-D</b>, Proportion of progeny within each phenotype category for expression with <i>da-GAL4</i> alone (left column), or in the presence of the <i>Dcr-1^Q1147X</i> mutant allele such that Dcr-1 levels are reduced (right column). <b>A</b>, wildtype control, <b>B</b>, <i>4xrCAA_∼100 [line 1],. </i><b>C</b>, <i>4xrCUG_∼100 [line 1],. </i><b>D</b>, <i>4xrCAG_∼100 [line 2]. </i><b>E, F</b>, Total proportion for each genotype that shows any phenotype (‘any phenotype’ - category 2, 3 and 4) and the proportion with a strong phenotype (‘strong phenotype’ – category 3 and 4). <b>E</b>, <i>4xrCUG_∼100 [line 1]</i> shows a suppression for both measures. <b>F</b>, <i>4xrCAG_∼100</i> [line 2] shows an enhancement for both measures. Comparisons were made between the populations using Fisher’s exact test, with significant results indicated above the proportion, where *p<0.05, **p<0.01 and ***p<0.001.</p