Fig. 4: Functional screening identifies KLF15 as an Mrps5 downstream target in the heart.

a Diagram of workflow for the selection of six Mrps5 downstream target genes from the 2926 downregulated genes identified in Mrps5^cKO hearts. b Expression of Klf15 and other top candidate genes in the hearts of Mrps5^fl/fl control and Mrps5^cKO hearts. c Decreased expression of Klf15 and other top candidate genes in Mrps5 knockdown cardiomyocytes. d Heatmap showing expression of Mrps5, Klf15, and other top candidate genes in TAC-induced hypertrophic mouse hearts. e Dysregulated expression of Mrps5, Klf15, and other top candidate genes in hearts of human dilated cardiomyopathy patients. f Heatmap of the relative gene expression for Mrps5, Klf15, and other top candidate genes in NMCMs after 12, 24, 48 h stimulation with ISO, PE, and FBS, respectively. g–l Pearson’ r correlation coefficient with corresponding P values for the covariation between Mrps5, Klf15, and other top candidate genes. m Experimental procedure for the use of AAV9-mediated expression of potential targets for functional screening in Mrps5^cKO mice. n M-mode echocardiography of Mrps5^cKO mice, 7 weeks after injection of indicated AAV9-construct. o Fractional shortening (FS%) of Mrps5^cKO mice, 7 weeks after injection with indicated AAV9-construct. p Ejection fraction (EF) of Mrps5^cKO mice, 7 weeks after injection with indicated AAV9-construct. q Immunohistology of heart sections of Mrps5^cKO mice, 7 weeks after injection with indicated AAV9-construct. DAPI labels the nucleus, WGA marks the cell membrane, and ACTN1 marks cardiomyocytes. Scale bars = 20 µm. r Quantification of sizes of cardiomyocytes from the previous experiment (Fig. 4q). s Sirius Red and Fast Green staining of heart sections of Mrps5^cKO mice, 7 weeks after injection of indicated AAV9-construct. Scale bars = 50 µm. The boxed area in the upper panel is shown magnified in the lower panel. t Quantification of fibrosis from the previous experiment (Fig. 4s). N numbers are indicated in each panel. All data were presented as mean ± SEM. P values were determined by one-way ANOVA with the Brown–Forsythe and Welch multiple comparisons test.