Fig. 5
Rbfox1 colocalizes with membraneless nuclear organelles associated with RNA metabolism. a In follicle cell nuclei, Rbfox1 is associated with chromatin and enriched in the granular component of the nucleolus. Rbfox1 upregulation in miR-980 mutants modifies nucleolar shape and size. b Quantifications of nucleolar type distribution in st.9-10 follicular epithelial cells (n = 273 cells for Control, 234 for miR-980Ex1-2 and 92 for Rbfox1 OE). c Increased Rbfox1 expression modifies nucleolar shape and size and CB size and numbers. Rbfox1-overexpressing clone is outlined by yellow line (hsFlp; UAS-Rbfox1/ + ; act > CD2 > Gal4 UAS-GFP). d Most of the st.9-10 follicle cells contain one CB, while Rbfox1-overexpressing cells have 1 to > 10 smaller CBs per cell (n = 199 and 156 cells, respectively). e Rbfox1 association with CBs is enhanced by miR-980 loss and stress. f Percentages of Rbfox1-positive CBs are significantly increased in miR-980 mutants in comparison to Control (n = 82 and 256 CBs, respectively). This tendency becomes even more pronounced upon starvation stress (n = 598 and 262 CBs for miR-980 and Control, respectively). g In the germline, Rbfox1 colocalizes with CBs (blue arrowheads) and this colocalization is enhanced by miR-980 loss and stress. Rbfox1 can be also detected in the nuage of the germline nurse cells (white arrowheads). In starved miR-980 mutants, Rbfox1-positive fibers can be observed (yellow arrows, right panel). Rbfox1 (green); DAPI (blue); Fibrillarin (nucleolus, red, a–c); Coilin (CB, cyan, c, red, e, g). Follicular epithelial cells (a–c, e), germline nurse cells (f). Images in a, b, e–g - single Z-sections, c - maximum intensity projection of multiple Z-sections. Scale bars 5 µm. Two-Way Tables and Chi-square test were applied for statistics in b and f, ***p ≤ 0.001
