Fig. 1: pTINCR is an evolutionarily conserved microprotein highly expressed in epithelia.

a Screening of the coding potential of lncRNAs enriched in skin compared to other organs⁴⁴. PhyloCSF score was obtained from LNCipedia v.5.2. b Heat map of TINCR lncRNA expression in human and mouse tissues. Expression in human was obtained from GTEX. Expression in mouse was assessed by RT-qPCR (at least 3 mice per organ). Values represent the percentage of TINCR expression in each organ normalized to the expression in the skin. c Diagram of TINCR locus. pTINCR sORF is indicated with a big black square. In red, PhyloCSF score across TINCR. In green, Ribo-seq analysis of Tincr transcript in mouse skin. In blue, expression of Tincr in mouse skin by RNAseq. d pTINCR amino acid conservation across the tetrapoda taxa depicted by multiple sequence alignment performed by Clustal Omega. Amino acid colors indicate their properties (pink, positive charge; blue, negative charge; red, hydrophobic; green, hydrophilic). The symbols below the alignment represent the biochemical similarity (asterisks indicate identical conservation, colons high similarity and periods similar conservation). e Diagram of the constructs used for in vitro translation of pTINCR microprotein. f In vitro translation of WT and ATG^mut full-length TINCR lncRNA visualized by SDS-PAGE. Two experiments were performed and obtained similar results. g MS/MS spectrum of a unique peptide derived from pTINCR microprotein in human skin organotypic cultures. h Western blot analysis of endogenous pTINCR in a panel of mouse epithelial tissues. Adrenal gland and spinal cord were added as negative controls. The experiment was repeated 4 times obtaining similar results. i Representative immunostainings of pTINCR in mouse and human skin and liver using a pTINCR antibody. Liver was added as a negative control. Scale bars correspond to 100 µm. j Representative immunostainings of a panel of mouse stratified epithelia using a pTINCR antibody. Scale bars correspond to 100 µm. k Representative immunofluorescence images of HaCaT and MCF7 cells using a pTINCR antibody (green) and Phalloidin-TRITC (red). Scale bars correspond to 50 µm. Immunostainings were performed at least twice obtaining the same results. Source data are provided as a Source Data file.