Fig. 4: Define the characteristics and trajectory of SPRR1B+ keratinocyte cluster (KC4).

a–c Reconstruction of a trajectory with keratinous subpopulation; Results of pseudotime analysis of keratinocytes, colored by subclusters (Fig. 4a), pseudotime (Fig. 4b) and samples (Fig. 4c). d Expression levels for each cell are colored and overlaid onto pseudotime. Genes were selected as specifically expressed in celltypes. Bright yellow indicates maximum relative expression, and dark blue indicates low or no expression of this gene, each were accompanied by color-coded pseudotime feature plots. e, f Representative immunofluorescent images of normal skin and oral mucosa stained with the basal cell marker keratin 14 (K14, red), differentiation markers keratin 10 (K10, green), and Small Proline-Rich Protein IB (SPRR1B, green). Scale bar 50 µm. g Gene Ontology analysis of marker genes of the KC4 keratinocyte cluster. h The violin plot represents the gene expression levels in different group. i Gene scoring analysis of KC4 between oral and skin using the indicated molecular signatures. Two-sided Wilcoxon rank-sum tests were performed (h, i). ****p < 2.2e-16.