Figure 2.

Nocturnin Is Induced in BAT in Response to Acute Cold Exposure

(A) Biochemical fractionation of mitochondrial and cytoplasmic compartments in wild-type BAT, blotted for NOC, VDAC (mitochondrial outer membrane), MT-CO2 (mitochondrial matrix), and ACTIN (cytoplasm) proteins. Molecular weight markers are indicated in kilodaltons.

(B) qRT-PCR analysis of BAT samples from wild-type and Nocturnin^−/− littermates kept at room temperature (RT) or exposed to cold (6°C) for 4 h.

(C) Core body temperature of mice during prolonged cold exposure at 6°C; animals placed at cold at ZT1 (left) or ZT13 (right) (N = 8–10/genotype, yellow and gray shading indicating day and night, respectively).

(D) Transcript levels of Ucp1, Pparγ, PGC1α, and Dio2 genes normalized to B2M in BAT tissue of the indicated genotype and condition (N = 3–6). WR, wild-type room temperature; WC, wild-type cold; KR, Nocturnin^−/− room temperature; KC, Nocturnin^−/− cold.

(E) mtDNA copy numbers in BAT of mice kept at RT or cold (6°C, 4h) (N = 4–5).

(F) qRT-PCR analysis of mitochondrial-encoded genes in BAT. Transcript levels were normalized to mtDNA copy number. (N = 3–5).

(G) Average fold changes for mtDNA genes in response to a 4-h cold exposure in the indicated genotypes.

*p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 as analyzed by two-way analysis of variance (ANOVA) with a Tukey's post-hoc test (A, D, and F) or two-tailed Student's t test (C and G). Data are represented as mean ± SEM; ns, not significant.