Messenger RNA levels of growth factors, ligands, receptors, and proteins affecting lipid metabolism in pigs

The Northern blot technique was used for mRNA phenotyping of 19 growth factors, ligands, receptors, and proteins involved in lipid metabolism in two populations of pigs with different fat deposition capabilities. The mRNA levels were measured in backfat, liver, and muscle tissue at different slaughter weights, taking backfat thickness, gender and breed of the animals into consideration. Of all the RNA patterns measured in the Landrace population, only the mRNA transcript level of low density lipoprotein receptor-related protein (also called alpha 2-macroglobulin receptor) was associated with the pig's backfat thickness phenotype in muscle and backfat tissues. In the population composed of purebred Yorkshire and Hampshire, epidermal growth factor receptor, malic enzyme, platelet derived growth factor β and insulin-like growth factor binding protein 3 show different mRNA patterns associated with backfat thickness phenotypes. When analyzing the data using the gender or the breed as the main effect, the insulin receptor and insulin-like growth factor binding protein 1 were different between genders whereas insulin-like growth factor binding protein 3, malic enzyme, epidermal growth factor receptor and low density lipoprotein receptor-related protein were different between breeds. Analysis of this type should be helpful in understanding the regulation of fat deposition. Key words: mRNA levels, marker genes, backfat, pig