IGF2 is paternally expressed in fetal liver and muscle, and in piglet heart,
liver, brain, lung, kidney, stomach, pancreas, thymus, tongue, muscle, bladder, spleen and placenta.
The IGF2 P1 transcript is bi-allelically expressed (not imprinted) in all major organs studied
C, et al. 1999; Li
C, 2008). IGF2 DMRs have been reported (Han
DW, 2008). Bischoff SR et al, 2009 showed paternal
the P2, P3 and P4 transcripts in pig placenta, but failed to detect P1 transcript expression in any
of the tissues examined.
A quantitative trait locus (QTL) with postnatal effects on the lean meat content in ham, longissimus
muscle area, backfat thickness and heart weight is linked to pig IGF2 and is paternally inherited
JT, et al 1999; Nezer
C, et al. 1999; Nezer
C et al, 2003; Jungerius
BJ et al, 2004).
The QTL is caused by a nucleotide substitution in intron 3 of IGF2. The mutation does not seem
to affect the imprinting status of the allele, but it increases the expression of IGF2 from
promoters P2-P4 3-fold in postnatal skeletal muscle when homozygous or paternally inherited. The
mutation was shown to reduce interaction with some nuclear factor, possibly a repressor, which could
explain the increase in expression of IGF2 with this QTL (Van
Laere AS, et al. 2003).