Analysis of porcine IGF2 gene expression in adipose tissue and its effect on fatty acid composition

PLoS One. 2019 Aug 8;14(8):e0220708. doi: 10.1371/journal.pone.0220708. eCollection 2019.

Abstract

IGF2:g.3072G>A polymorphism has been described as the causal mutation of a maternally imprinted QTL for muscle growth and fat deposition in pigs. The objective of the current work was to study the association between the IGF2:g.3072G>A polymorphism and the IGF2 gene expression and its effect on fatty acid composition in adipose tissue in different pig genetic backgrounds. A cis-eQTL region associated with the IGF2 mRNA expression in adipose tissue was identified in an eGWAS with 355 animals. The IGF2 gene was located in this genomic interval and IGF2g.3072G>A was the most significant SNP, explaining a 25% of the gene expression variance. Significant associations between IGF2:g.3072G>A polymorphism and oleic (C18:1(n-9); p-value = 4.18x10-07), hexadecanoic (C16:1(n-9); p-value = 4.04x10-07), linoleic (C18:2(n-6); p-value = 6.44x10-09), α-linoleic (C18:3(n-3); p-value = 3.30x10-06), arachidonic (C20:4(n-6); p-value = 9.82x10-08) FAs and the MUFA/PUFA ratio (p-value = 2.51x10-9) measured in backfat were identified. Animals carrying the A allele showed an increase in IGF2 gene expression and higher PUFA and lower MUFA content. However, in additional studies was observed that there could be other proximal genetic variants affecting FA composition in adipose tissue. Finally, no differences in the IGF2 gene expression in adipose tissue were found between heterozygous animals classified according to the IGF2:g.3072G>A allele inherited from the father (APGM or AMGP). However, pyrosequencing analysis revealed that there is imprinting of the IGF2 gene in muscle and adipose tissues, with stronger differences among the paternally and maternally inherited alleles in muscle. Our results suggested that IGF2:g.3072G>A polymorphism plays an important role in the regulation of IGF2 gene expression and can be involved in the fatty acid composition in adipose tissue. In both cases, further studies are still needed to deepen the mechanism of regulation of IGF2 gene expression in adipose tissue and the IGF2 role in FA composition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / metabolism*
  • Alleles
  • Animals
  • Fatty Acids / analysis*
  • Fatty Acids / chemistry
  • Fatty Acids, Monounsaturated / analysis
  • Fatty Acids, Unsaturated / analysis
  • Gene Expression Regulation
  • Genome-Wide Association Study
  • Insulin-Like Growth Factor II / genetics
  • Insulin-Like Growth Factor II / metabolism*
  • Polymorphism, Single Nucleotide
  • Quantitative Trait Loci
  • Swine

Substances

  • Fatty Acids
  • Fatty Acids, Monounsaturated
  • Fatty Acids, Unsaturated
  • Insulin-Like Growth Factor II

Associated data

  • figshare/10.6084/m9.figshare.8158922

Grants and funding

This work was supported by the Spanish Ministerio de Economía y Competitividad (MINECO) and the Fondo Europeo de Desarrollo Regional (FEDER) with project references: AGL2014-56369-C2 and AGL2017-82641-R (http://www.mineco.gob.es/portal/site/mineco/ and http://ec.europa.eu/regional_policy/es/funding/erdf/). LCM was financially supported by a FPI grant from the AGL2014-56369-C2 project. MB was funded with a “Ramón y Cajal” contract (RYC-2013-12573) from the Spanish Ministerio de Economía y Competitividad. DCP was funded by a “Formació i Contractació de Personal Investigador Novell” (FI-DGR) Ph.D grant from the Generalitat de Catalunya (ECO/1788/2014). We acknowledge the support of the Spanish Ministerio de Economía y Competitividad for the “Severo Ochoa Programme for Centres of Excellence in R&D” 2016-2019 (SEV-2015-0533) to the Centre for Research in Agricultural Genomics and the CERCA Programme / Generalitat de Catalunya. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.