Figure 3.

Changes induced by silencing Scrt1 were anti-correlated with the maturation signature of islet cells. FAC-sorted adult rat β-cells were transfected with a control siRNA (siCtl) or siRNAs directed against Scrt1 (siScrt1). RNA extraction and library preparation for RNA-seq were performed 48 h post-transfection. (a) Volcano plot of gene expression changes induced by Scrt1 knockdown. SCRT1 putative target genes (defined based on the presence of SCRT1 motif in ACS in the proximity of the gene) significantly altered are indicated with red dots and labels. In the top left, normalized counts from the RNA-seq data of Scrt1 expression is represented with a barplot. (b) log₂ fold changes distribution of significantly altered genes by siScrt1 containing a SCRT1 motif in an ACS either at the TSS (± 1Kbp), proximal (1-10Kbp) or distal (more than 10Kbp) from the gene. (c) Scatter plot of log₂ fold changes of differentially expressed genes from adult/P10 measured by micro-array (n = 3) versus log₂ fold changes of siScrt1/control measured by RNA-seq (n = 5). Several genes of interest are represented with their label. (d) Enrichment plot for two significant annotations using the FGSEA algorithm. (e) Scheme describing the siScrt1 hypothesis. Briefly, the siRNA for Scrt1 will reduce the mRNA level of the Scrt1 gene and consequently the level of the protein. Thus, lower binding of SCRT1 will occur at target sites that will affect proliferation and specialization of β-cells. qPCR confirmation of gene expression in (f) FAC-sorted β-cells transfected with siCtrl or siScrt1 or in (g) P10 versus adult rat islets. Student T test, *p < 0.05, **p < 0.01. See also Supplementary Fig. S5 and Supplementary Tables 5, 6, 7, 8.