CLDN7 RNA synthesis increases during differentiation. A: CLDN7 mRNA and heteronuclear RNA (hnRNA) levels were detected in Caco-2 intestinal epithelial cells (IECs) during differentiation. CLDN7 mRNA and hnRNA increases 10- and 20-fold, respectively, after 3 days in culture compared with day 1. The increase is 20- and 40-fold, respectively, after 6 days. qPCR reactions were performed in triplicate, results are represented as the average of the triplicates. B: Schematic representation of the CLDN7 gene (marked gDNA for genomic DNA), nascent hnRNA, and mRNA structure. Forward (Fw) and reverse (Rv) primer locations for PCR detection are indicated on the diagrams. UTR, untranslated region.