Presence of a novel exon 2E encoding a putative transmembrane protein in human IL-33 gene

► Promoter usage of IL-33 is dependent on cell type. ► A novel exon 2E is found in the conventional intron 2 of IL-33 gene. ► Exon 2E encodes putative transmembrane protein of 131 amino acids. ► Expression of exon 2E is suggested to be dependent on differentiation of HUVEC cells.