Gene expression profiling in a congenic strain identifies candidate genes for nutrient intake QTL on mouse chromosome 17

The goal of this experiment was to identify genes contributing to fat, carbohydrate, and total calorie intake in mice by comparing gene expression in liver and hypothalamus of an interval-specific congenic strain, B6.CAST-17, with that of the control strain. This congenic strain has previously confirmed genetic loci on Chr 17 linked to increased carbohydrate (Mnic1) and kilocalorie (Kcal2) intake. Keywords: Comparative gene expression analysis RNA obtained from six male B6.CAST-17 homozygous congenic mice and six male wild type B6 mice was pooled. Gene expression in hypothalamus and liver was compared between the strains under two diet conditions: 1) chow (LabDiet #5001) and 2) 78% carbohydrate/22% protein vs. 78% fat/22% protein, 4 h before lights out on day 2. Mice were selected based on phenotypic variation; specifically, 20-25 mice of each strain were tested in a self-selection diet protocol for 10 days. Mice that displayed the most divergent phenotypic values for nutrient intake (kcal per body weight) were chosen for study, returned to chow diet for 6 wks, and then returned to the 2-choice diet for one day.