GRK 1208/2: Molecular Mechanisms Leading to a Distortion of Hormonal Regulation and Energy Imbalance as a Result of Selection and Excessive Energy Supply in the Berlin Fat Mouse Line

All experiments are based on the Berlin Fat Mouse model for polygenic obesity.
For finemapping of target regions, we will use an advanced intercross population (AIL), which has been generated from the original mapping cross BFMI x B6. To confirm the effect of the most likely fine mapped region, recombinant animals will be selected and crossed back to B6 mice to generate congenic strains. Evidence for interaction between two genomic loci will be provided by crossing of mice harbouring the chr 3 mutation and a second locus, which has been suggested by statistical analyses (previous work). Male and female offspring will be characterized on standard breeding (SBD) and high fat diet (HFD) to pinpoint sex-specific and diet effects on obesity. Sequencing of fine mapped chr regions and in silico search for putative functional effects of DNA variants will be performed by an associated PhD student in a different project. We will select animals with different genotypes from our different genetic models to study expression levels on SBD and HFD of the target gene(s), possibly genetically linked genes (genes neighboured to the target gene) and putative down-stream regulated genes in adipose tissues, muscle, liver and brain. In addition, we will analyze the influence of the mutant gene on fatty acid composition and gene expression in adipocytes. To identify the effected cellular mechanism by the mutant gene product, we will perform siRNA silencing of the target gene in 3T3 adipocyte cell culture and/or in generated BFMI specific adipocyte cell cultures for complementation tests.