Figure 2. The mRNA expression levels of 21 gap junction channel genes in normal human TM cells. A: Mean cycle threshold Ct values were determined using real-time PCR (RT–PCR) using cDNAs from three individuals (n=3). The Ct values for the GJA1, GJA8, GJB6, GJC1, and GJD4 gene expression levels were compared with that of GAPDH. B–D: Transcriptional levels of the GJA1, GJA8, GJB6, GJC1, and GJD4 genes in donors 1 to 3 were normalized to the mRNA level of GAPDH. The GJA1 gene, also known as connexin 43, showed the highest expression level. Three independent experiments were performed (n=3). * p≤0.05.