Synergistic Activations of REG Iα and REG Iβ Promoters by IL-6 and Glucocorticoids through JAK/STAT Pathway in Human Pancreatic β Cells

Figure 4

IL-6 + Dx-induced transcription of REG Iα and REG Iβ in human 1.1B4 β cells is dependent on the JAK/STAT pathway. (a) IL-6 + Dx-induced REG Iα promoter activation in 1.1B4 cells. (b) Sequences of the human REG Iα and REG Iβ promoters. Putative STAT-binding site is underlined. Nucleotide substitutions in the STAT-binding site are indicated by lower-case letters. (c) Effects of site-directed mutation on IL-6 + Dx-induced REG Iα promoter activation. (d) Effects of AG490, a JAK inhibitor, on IL-6 + Dx-induced REG Iα promoter activity. 1.1B4 cells were transfected with indicated construct. (e) IL-6 + Dx-induced REG Iβ promoter activation in deleted and mutated promoter. (f) Effects of JAK inhibitor on IL-6 + Dx-induced REG Iβ promoter activity. Fold increase is calculated by dividing the promoter activity of IL-6 + Dx treated cells by that of untreated cells. Data are expressed as means ± SE for each group ((a) , (c) -4, (d) , (e) -4, (f) ). ; .

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