Fig. 5

TRPS1 maintains LP function by repressing SRF/MRTF activity a UMAP dimensionality reduction plots of the re-clustered luminal population from CITE-Seq (Fig. 3). From left to right: Graph-based clusters, Highlight of shTrps1 (red) and shRen (blue) cells, luminal progenitor and luminal mature gene set (Fig. 3c) activity based on AUCs and Trps1 mRNA expression. b Volcano plot of the differential gene expression in shTrps1 vs shRen luminal progenitors (Cluster 2). padj = adjusted p-value, FC = Fold Change. c–e Volcano plots of processes enriched in genes down regulated (c), processes enriched in genes up regulated d and TF motifs enriched in genes up regulated in shTrps1 vs shRen luminal progenitor cells e. FDR = False Discovery Rate. f Expression of SRF/MRTF target genes Cald1 and Actn1 in luminal progenitor cluster 2 in shTrps1 (red) and shRen (blue). g UMAP dimensionality reduction plot of SRF/MRTF gene set activity based on AUCs. h, i UMAP dimensionality reduction plot of Cald1 h and Cyr61 i mRNA expression. j Heatmap of the differentially expressed genes in each cluster of shRen control cells. k Violin plots of SRF/MRTF (left) and YAP (right)-targets gene set activities in the indicated clusters. l CytoTRACE pseudotime trajectory of luminal cells in shRen control animals m Experimental design: SRF was activated in mammary organoids by Cytochalasin D treatment and gene expression changes evaluated by qRT-PCR. n Heatmap based on qRT-PCR of SRF targets (Cald1, Acta2, Myl9), luminal progenitor markers (Kit, Cd14, Elf5), Trps1 and the YAP-SRF joint target Ctgf in mammary gland organoids treated for 3 days with Cytochalasin D (2 µM) or DMSO. o Schematic of SRF activation in Colony forming assay with sorted luminal progenitor cells. p well area covered by colonies formed by luminal progenitor cells treated with cytochalasin D (0.2 µM), Y-27632 (10 µM) or DMSO as control. right side: representative pictures of colonies stained with Giemsa. One-way ANOVA, with Tukey HSD, post-hoc test. Indicated p values are p adjusted