Disease relevance of IGF2

• The RYR1 g.1843C>T mutation is associated with the effect of the IGF2 intron3-g.3072G>A mutation on muscle hypertrophy [1].

High impact information on IGF2

• A paternally expressed QTL affecting skeletal and cardiac muscle mass in pigs maps to the IGF2 locus [2].
• By identifying a haplotype shared by all "Q" chromosomes, we map the QTL to an approximately 250-kb chromosome segment containing INS and IGF2 as the only known paternally expressed genes [3].
• Haplotype sharing refines the location of an imprinted quantitative trait locus with major effect on muscle mass to a 250-kb chromosome segment containing the porcine IGF2 gene [3].
• A paternally expressed quantitative trait locus (QTL) for muscle mass was mapped to the insulin-like growth factor II (IGF2) locus at the distal end of pig chromosome 2p [4].
• Further, the significant difference found in expression of IGF2-AS in postnatal muscle between individuals with different QTL genotypes and the lack of significant differences in fetal muscle and liver reflect completely what has been found for IGF2 sense transcripts [4].

Biological context of IGF2

• Comparative sequence analysis of the INS-IGF2-H19 gene cluster in pigs [5].
• New SNPs in the IGF2 gene and association between this gene and backfat thickness and lean meat content in Large White pigs [6].
• Effects of weaning on somatotrophic gene expression and circulating levels of insulin-like growth factor-1 (IGF-1) and IGF-2 in pigs [7].
• Liver RNA was analyzed for mRNAs specific for the GH receptor, IGF-1, IGF-2, and IGF binding protein 3 [8].
• Complete food withdrawal from pregnant guinea pigs for 2 days at days 43-44 of pregnancy caused mild fetal growth retardation and similar changes in plasma constituents, except in that plasma IGF-2 concentrations were now depressed and plasma was not inhibitory to sulphate incorporation into pig costal cartilage [9].

Anatomical context of IGF2

• In contrast, adipose tissue IGF-1 and IGF-2 mRNA levels were greatest in the small piglets (P = 0.001 and 0.029, respectively) [7].
• It also elevated fetal plasma concentrations of insulin, IGF-1, IGF-2, sulphation-promoting activity, thyroid hormones, glucose and free fatty acids and depressed that of glucagon and amino acids [9].

Associations of IGF2 with chemical compounds

• A paternally expressed QTL affecting muscle growth, fat deposition and size of the heart in pigs maps to the IGF2 (insulin-like growth factor 2) region [10].
• Uterine artery ligation at day 30 of pregnancy depressed fetal growth rate by greater than 50% and was associated with falls in plasma insulin, IGF-1, cortisol, thyroid hormone, glucose, acetate and free fatty acid concentrations and rises in that of IGF-2, glucagon and amino acids [9].

Regulatory relationships of IGF2

• This study demonstrates that the IGF2 mutation also controls the paternally expressed QTL for backfat thickness in a cross between Meishan and European Whites [11].
• Finally, this study shows that this particular IGF2 mutation does not cause the paternally expressed QTL for teat number mapping to the same region of SSC2p as the BFT QTL [11].

Other interactions of IGF2

• Recently, a mutation in a regulatory element of the IGF2 gene was identified as the quantitative trait nucleotide (QTN) underlying the major QTL effect on muscle growth and BFT in crosses between Large White and Wild Boar or Pietrain [11].
• A total of 33 QTL with parent-of-origin effects were identified, including QTL with paternal expression for backfat and loin muscle area on chromosome 2, near IGF2, and QTL with maternal expression for drip loss and reflectance on chromosome 9 [12].
• Blood samples were collected at the time of sacrifice and analyzed for serum concentrations of GH, insulin-like growth factor 1 (IGF-1), and IGF-2 [8].
• Treatment with GH increased circulating levels of GH and IGF-1 (P < 0.01), but not PRL, TSH, or IGF-2 [13].
• 2. Developmentally, hepatic IGF-2 (P < 0.05) and IGFBP-2 (P < 0.01) mRNA levels were higher fetally and at birth than at 21 and 49 days of age [14].

References