Figure 8. The endoplasmic reticulum (ER) stress response induced in Muc2^−/− intestinal epithelial cells.

The stress response was investigated in the SI-IECs of Muc2^−/− mice by analyzing the relative levels of unspliced Xbp1(u) and spliced Xbp1 (s) mRNA. (A) shows the gel analysis of PCR reactions, detecting unspliced and spliced forms of Xbp1 in purified SI-IECs of mice of the indicated genotypes. (B) and (C) show quantification of the bands in A for total Xbp1 mRNA relative to β-actin (B) and the relative levels of spliced versus unspliced forms of Xbp1 (C). (D) The level of expression of the indicated ER stress responsive genes was determined by qRT-PCR in WT and Muc2^−/− SI-IECs. (E) shows immunohistochemical detection of Grp78 in the small intestine of WT and Muc2 ^−/− mice.