Figure 1.

Interleukin-33 (IL-33) mRNA expression in THP-1 macrophages. A, The human IL-33 gene includes 3 exon 1 variants named 1a, 1b, and 1c (Tominaga et al., 2013). The position of each exon is described. The mRNA variants with exons 1a, 1b, or 1c are registered in the GenBank as variant 4, variant 1, or variant 5, respectively, and are translated into the same protein because exons 2 (includes the start codon) to 8 are common among the 3 variants. B, The primer positions used to detect the mRNA levels of total human IL-33 and variants 1, 4, and 5 are shown. C, Total RNA was extracted from THP-1 macrophages, and cDNA was synthesized. IL-33 mRNA levels were measured by real-time PCR. The values represent the mean ± SE (n = 4).