Figure 5. Hrd1, but not Ire1α of UPR, controls mitochondrial morphology and thermogenesis in brown adipocytes.
(A) Rectal temperature of 8- to 10- week-old Hrd1f/f and Hrd1Ucp1Cre mice housed at 22°C or 4°C for 6 hr, n=4/group (one-way ANOVA). (B-D) Representative TEM images of BAT from Hrd1f/f and Hrd1Ucp1Cre mice housed at 22°C or 4°C for 6 hr with quantitation shown in C. n= 543, 581 mitochondria for 22°C and 4°C, Student’s t-test. Yellow arrows, megamitochondria; red arrows, ER tubules within mitochondrial profiles. (E) RT-PCR analysis of Xbp1 mRNA splicing in BAT at 22°C or 4°C for 6 hr with quantitation of the ratio of spliced Xbp1 (s) to total Xbp1 (spliced + unspliced (u)) shown below the gel (n = 6 mice per group). BAT from wildtype mice injected with vehicle or tunicamycin (Tuni, 1 mg/kg) included as controls. (F-G) Representative TEM pictures of BAT from Ire1aAdipCre mice at 4°C for 6 hr with quantitation shown in G (n=500, 665 from 2 mice each, Student’s t-test). All experiments have been repeated two to three times. Data are mean ± SEM. **, p< 0.01; ***, p< 0.001.