Insulin Like Growth Factor 2 Expression in the Rat Brain Both in Basal Condition and following Learning Predominantly Derives from the Maternal Allele

PLoS One. 2015 Oct 23;10(10):e0141078. doi: 10.1371/journal.pone.0141078. eCollection 2015.


Insulin like growth factor 2 (Igf2) is known as a maternally imprinted gene involved in growth and development. Recently, Igf2 was found to also be regulated and required in the adult rat hippocampus for long-term memory formation, raising the question of its allelic regulation in adult brain regions following experience and in cognitive processes. We show that, in adult rats, Igf2 is abundantly expressed in brain regions involved in cognitive functions, like hippocampus and prefrontal cortex, compared to the peripheral tissues. In contrast to its maternal imprinting in peripheral tissues, Igf2 is mainly expressed from the maternal allele in these brain regions. The training-dependent increase in Igf2 expression derives proportionally from both parental alleles, and, hence, is mostly maternal. Thus, Igf2 parental expression in the adult rat brain does not follow the imprinting rules found in peripheral tissues, suggesting differential expression regulation and functions of imprinted genes in the brain.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Animals
  • Avoidance Learning / physiology
  • Base Sequence
  • Crosses, Genetic
  • DNA Methylation
  • Female
  • Gene Expression Regulation
  • Genomic Imprinting*
  • Hippocampus / chemistry
  • Hippocampus / physiology*
  • Insulin-Like Growth Factor II / genetics*
  • Insulin-Like Growth Factor II / metabolism
  • Kidney / chemistry
  • Liver / chemistry
  • Male
  • Memory, Long-Term / physiology
  • Molecular Sequence Data
  • Prefrontal Cortex / chemistry
  • Prefrontal Cortex / physiology*
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Inbred F344
  • Sequence Alignment
  • Sex Factors
  • Spleen / chemistry


  • IGF2 protein, human
  • RNA, Messenger
  • Insulin-Like Growth Factor II