Fig. 3
From: XBP1-mediated transcriptional regulation of SLC5A1 in human epithelial cells in disease conditions
XBP1 upregulates the expression of SLC5A1. (A) Left: western blot of SGLT1 and XBP1s in CFBE-WT (WT) and CFBE-dF (dF) cells transduced with Ad-LacZ or Ad-XBP1s or without any viral infection (Con). Right: SLC5A1 mRNA levels in WT and dF cells transduced with Ad-LacZ or Ad-XBP1. (B) Western blot of SGLT1 and XBP1s in CFBE-WT (WT) and CFBE-dF (dF) cells transduced with Ad-LacZ or AD-K907A (the dominant negative IRE1α) or without any viral infection (Con). (C) ChIP assay of CFBE-WT (WT) and CFBE-dF (dF) cells transduced with Ad-LacZ or Ad-XBP1s. The binding of XBP1 to the SLC5A1 promoter was determined by qPCR. (D) Top: illustration of the putative wild-type (wt) binding sequence (from − 595 to -583) or the mutated binding sequence (mut) of the reporter plasmid. Red colored letters indicated mutated sequences. Bottom: relative firefly/renilla luciferase signal levels in CFBE-WT (WT) and CFBE-dF (dF) cells transfected with different combinations of the reporter plasmids (wt or mut) and the Ad viruses (Ad-LacZ or Ad-XBP1s).