Rat IGF-I cDNA's contain multiple 5′-untranslated regions

Charles T. Roberts, Stephen R. Lasky, William L. Lowe, Derek LeRoith

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


DNA sequencing of several independent rat IGF-I cDNA clones has revealed three different 5′-untranslated region sequences which contain multiple, upstream, in-frame initiation codons. Use of these codons could generate N-terminal heterogeneity in IGF-I precursor proteins. One of these 5′-untranslated region sequences contains a 40-bp segment which is an inverted repeat of a region in the common 3′-untranslated region. The ends of the IGF-I mRNA corresponding to this cDNA could form a stable duplex structure. Such a complex could prevent ribosomal access to the AUG codons preceeding the coding region for the pre-pro-IGF-I peptide, suggesting the possibility of translational regulation of this form of IGF-I mRNA. The 3′-untranslated region inverted repeat sequence also is present in human and mouse IGF-I cDNA's, and, intriguingly, is more highly conserved than the rest of the 3′-untranslated region.

Original languageEnglish (US)
Pages (from-to)1154-1159
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number3
StatePublished - Aug 14 1987
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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