Fig. 1

Serum deprivation stress promotes expression of p113 derived from a circRNA of CUX1 in NB. a Heatmap of proteomics (left panel) and Venn diagram (right panel) showing altered proteins in SH-SY5Y and SK-N-BE(2) cells treated by serum deprivation (SD) for 24 h, and overlapping analysis with established transcription factors derived from Genomatrix database (http://www.genomatix.de). b Western blot assay indicating the expression of CUX1 isoforms and TCF3 in SH-SY5Y and SK-N-BE(2) treated with SD as indicated. c Mass spectrometry assay revealing amino acid sequence of p113 recovered from electrophoresis gel, with additional amino acids produced by ecircCUX1 (red). d Schematic illustration showing the genomic location of ecircCUX1 generated from exons 9-11 of CUX1, and validation by RT-PCR using convergent or divergent primers and Sanger sequencing. e Western blot assay (right panel) indicating endogenous and exogenous expression of p113 in SH-SY5Y cells stably transfected with empty vector (mock), wild-type or mutant 3Flag-tagged ecircCUX1 as indicated (left panel). f Western blot assay showing the levels of p113 and CUX1 isoforms in SH-SY5Y cells stably transfected with mock or ecircCUX1, and those treated with or without SD for 24 h. g Schematic illustration indicating genomic knockin (KI) of 3Flag-tagged or mutant (Mut) form of ecircCUX1 using CRISPR-Cas9. h Western blot assay revealing endogenous and exogenous expression of p113 in HEK293T and SK-N-BE(2) cells with genomic knockin (KI) of 3Flag-tagged or mutant (Mut) form of ecircCUX1. Fisher’s exact test for overlapping analysis in a. Data are representative of three independent experiments in b, d-f and h