Fig. 7: SOX21A is down-regulated in aged flies and functions downstream of InR.

a–d Representative immunofluorescence images of midguts from 14d flies (NRE-GFP; Sox21a-HA) without BLM treatment (as mock, a), 40d flies without BLM treatment (b), 14d flies treated with BLM (c), and 40d flies treated with BLM (d). SOX21A was labeled by HA (red). Armadillo (Arm, white) labeled plasma membrane. Yellow arrows indicate EBs. e Quantification of fluorescent intensity of SOX21A-HA in NRE-GFP⁺ EBs of midguts of experiments (a-d). Each dot represents one NRE-GFP⁺ EB. From left to right, n = 107, 119, 90, and 98, respectively. f–j Representative immunofluorescence of midguts with ISC-GFP (green), NRE-lacZ (red) and Pros (white) staining from 10d flies expressing UAS-GFP (used as control, f), UAS-sox21a RNAi (g), UAS-InR^CA (h), UAS-sox21a (i), and UAS-sox21a, UAS-InR^CA (j) driven by ISC^ts-Gal4. Yellow arrows indicate esg⁺Pros⁺ pre-EE cells. k–l Quantification of the number of esg⁺NRE^-Pros^- ISCs (k) and NRE⁺ EBs (l) per ROI with indicated genotypes of midguts in experiments (f–j). m The ratio of pre-EE to total esg⁺ cells per ROI with indicated genotypes of midguts in experiments (f–j). n The percentage of differentiated cells and esg⁺ cells to total cells with indicated genotypes of midguts in experiments (f–j). DAPI-stained nuclei (blue). Scale bar, 10 μm in (a–d) and 25 μm in (f–j). For dot plots, bars are mean ± SD. For box plots, box shows median, 25th and 75th percentiles and whiskers represent minima and maxima. Statistics were measured by one-way ANOVA. Each dot represents one ROI in (k–n). From left to right, n = 18, 15, 18, 15, and 15, respectively in (k–n). Source data are provided as a Source Data file.