Insulin-like growth factor II precursor gene organization in relation to insulin gene family

Nature. 1984 Aug 30-Sep 5;310(5980):777-81. doi: 10.1038/310777a0.


The insulin gene family, comprised of insulin, relaxin, insulin-like growth factors I and II (IGF-I and IGF-II) and possibly the beta-subunit of 7S nerve growth factor, represents a group of structurally related polypeptides whose biological functions have diverged. The IGFs, or somatomedins, constitute a class of polypeptides that have a key role in pre-adolescent mammalian growth (see ref. 4 for review). IGF-I expression is regulated by growth hormone and mediates postnatal growth, while IGF-II appears to be induced by placental lactogen during prenatal development. The primary structures of both human IGFs have been determined and are closely related. A polypeptide highly homologous to human IGF-II is secreted by the rat liver cell line, BRL-3A. As this polypeptide, termed multiplication stimulating activity (MSA), differs from human IGF-II by only five amino acid residues, MSA probably represents the rat IGF-II protein. Using molecular cloning techniques, we have isolated cDNA and chromosomal genes coding for the MSA and human IGF-II precursors, respectively. Our data, presented here, indicate that both MSA and human IGF-II are synthesized initially as larger precursor molecules. The deduced preprohormones both have molecular weights (MWs) of 20,100 and contain C-terminal propeptides of 89 amino acid residues, which we have named E-peptides. The organization of the IGF-II precursor gene is discussed in relation to that of other insulin gene family members.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • DNA / isolation & purification
  • Genes*
  • Humans
  • Insulin / genetics*
  • Insulin-Like Growth Factor II*
  • Mice
  • Nucleic Acid Hybridization
  • Protein Biosynthesis
  • Protein Precursors / genetics*
  • Rats
  • Rats, Inbred BUF
  • Somatomedins / genetics*
  • Structure-Activity Relationship


  • Insulin
  • Protein Precursors
  • Somatomedins
  • preproinsulin-like growth factor II
  • Insulin-Like Growth Factor II
  • DNA

Associated data

  • GENBANK/M13969
  • GENBANK/M13970
  • GENBANK/M14116
  • GENBANK/M14117
  • GENBANK/M14118