Adipose subtype-selective recruitment of TLE3 in thermogenic gene programs

Transcriptional effectors of white adipocyte-selective gene expression have not been described. TLE3 is a white-selective cofactor that acts reciprocally with the brown-selective cofactor Prdm16 to specify lipid storage and thermogenic gene programs. When expressed at elevated levels in brown fat, TLE3 counters Prdm16, suppressing brown-selective genes and inducing white-selective genes, resulting in impaired fatty acid oxidation and thermogenesis. To further test the functional consequences of the changes in BAT phenotype in aP2-TLE3 Tg mice, we challenged them with cold exposure at 4C. aP2-TLE3 Tg mice had an impaired ability to respond to cold exposure compared to littermate control mice, as evidenced by a marked drop in core body temperature. Transgenic mice expressing TLE3 from the aP2 enhancer and wild type mice were housed individually without food and bedding immediately before the start of experiments. Mice were allowed free access to water and placed at 4C for 5 hours while core body temperature was monitored every hour using a rectal probe. For microarray experiments of BAT, RNA was extracted and pooled from 4 mice in each group.