Fig. 7: The C19F variant in MGP results in ER stress in vivo.

a Immunofluorescence imaging using an anti-calnexin antibody shows the upregulation of calnexin in the prehypertrophic and hypertrophic chondrocytes in the growth plates of 3-week-old Mgp+/56G>T mice. DAPI stains the nuclei (blue). b Schematic representation of three major ER stress pathways involving ATF6, PERK and IRE1α and their downstream effectors N-terminal fragment of ATF6 (ATF6-N), phosphorylated eIF2α (peIF2α) and the spliced form of XBP1 (sXBP1), respectively. Confocal immunofluorescence images of vertebral sections from 3-week-old control and Mgp+/56G>T mice using anti-ATF6-N (c), anti-p-eIF2α (d), anti-sXBP1 (detects the spliced form) (e), and anti-CHOP antibodies (f) show increased accumulation of these markers, except for the spliced XBP1 in the latter genotype. Arrows on the immunofluorescence images indicate the protein localization.