At least six nucleotides preceding the AUG initiator codon enhance translation in mammalian cells

J Mol Biol. 1987 Aug 20;196(4):947-50. doi: 10.1016/0022-2836(87)90418-9.


Sequences flanking the AUG initiator codon influence its recognition by eukaryotic ribosomes. From a comparison of several hundred mRNA sequences, CCA/GCCAUGG emerged as the consensus sequence for initiation in higher eukaryotes. Systematic mutagenesis of a cloned preproinsulin gene confirmed the facilitating effect of A or G in position -3 (i.e. 3 nucleotides upstream from the AUG codon), C in positions -1 and -2, and G immediately following the AUG codon. The analysis of a new set of mutants now reveals that sequences slightly farther upstream are also influential, the optimal context for initiation being (GCC)GCCA/GCCAUGG. Possible mechanistic implications of the repeating GCC motif are discussed.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • Codon*
  • Insulin
  • Mutation
  • Proinsulin / genetics
  • Protein Biosynthesis*
  • Protein Precursors / genetics
  • RNA, Messenger*


  • Codon
  • Insulin
  • Protein Precursors
  • RNA, Messenger
  • preproinsulin
  • Proinsulin