Discovery of novel alternative splicing pattern within exon 27 of hTRPA1. (A) Schematic demonstrating the strategy of performing transcript scanning across mRNA of human and mouse TRPA1. First round PCR was performed to amplify the full-length transcript as indicated by the green and red arrows. Subsequently, second round PCR spanning exon 24 to exon 27 as indicated by the blue and purple arrows was performed to screen alternative splicing pattern. (B and C) RT-PCR result of full-length PCR and transcript scanning across exon 24 to 27 of hTRPA1 transcript respectively. (D and E) RT-PCR result of transcript scanning mTrpa1 format as in B and C. (F) Top, nucleotide sequence of exon and intron boundaries across exon 26 to exon 27 of hTRPA1. Bottom, usage of 3 different splice acceptor sites of exon 27 give rise to WT or 27A and 27B splice variant respectively. (G), Top, schematic protein structure of the TRPA1 channel. The green, blue, and red boxes indicate the ankyrin repeat domain, 6 transmembrane domains and the position of the coiled-coil domain, respectively. Bottom, alignment of amino acid sequences of WT, 27A, and 27B. The arrow and number indicate position of amino acids. TRPA1, transient receptor potential ankyrin 1.