Molecular characterization of a region in IGF2 intron 3 harbouring a quantitative trait nucleotide affecting muscle growth in the pig

A paternally expressed quantitative trait locus (QTL) affecting muscle growth, fat deposition and heart size has been identified at the distal tip of pig chromosome 2p. We have recently shown that the QTL is caused by a G→A transition at position IGF2-intron3-3072.This localizes the mutation in an evolutionary conserved CpG-island that is hypomethylated in skeletal muscle. Furthermore, we have demonstrated by electrophoretic mobility shift assay and transient tranfection analyses of murine C2C12 myoblasts that the quantitative trait nucleotide (QTN) prevents the binding of a repressor in vitro. In the present study we report DNase I footprinting of the 300bp surrounding the QTN. The characterization of this CpG-island will help us to further elucidate the mechanisms underlying the QTL effect as well as to increase our general knowledge of the complex regulation of IGF2expression.