Alternative splicing produces messenger RNAs encoding insulin-like growth factor-I prohormones that are differentially glycosylated in vitro

Mark A. Bach, Charles Roberts, Eric P. Smith, Derek LeRoith

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

Rat insulin-like growth factor-I (IGF-I) cDNA sequences predict two prohormones that differ in the carboxy-terminal extension peptide (E-peptide) as a result of the inclusion or exclusion of the 52-basepair exon 4 sequence. In the absence of exon 4, the sequence codes for the IGF-Ia prohormone, whose E region contains two potential N-glycosylation sites. With differential splicing and the inclusion of exon 4, the resultant mRNA codes for IGF-Ib, with a longer E-region sequence. In addition, as a consequence of a frame shift, both potential glycosylation sites are lost in the IGF-Ib peptide. We used an in vitro translation system supplemented with canine pancreatic microsomal membranes to analyze cotranslational processing of the IGF-I propeptides. We have demonstrated that the IGF-Ia prohormone, which contains two potential N-glycosylation sites in the E region, can be N-glycosylated in vitro, and that both glycosylation sites are probably used. As expected, the IGF-Ib preprohormone is processed by microsomes, but is not glycosylated.

Original languageEnglish (US)
Pages (from-to)899-904
Number of pages6
JournalMolecular Endocrinology
Volume4
Issue number6
StatePublished - Jun 1990
Externally publishedYes

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Alternative Splicing
Insulin-Like Growth Factor I
Glycosylation
Exons
Messenger RNA
Peptides
Microsomes
Canidae
Complementary DNA
Membranes
In Vitro Techniques
insulin-like growth factor 1A prohormone (91-103)

ASJC Scopus subject areas

  • Molecular Biology
  • Endocrinology, Diabetes and Metabolism

Cite this

Alternative splicing produces messenger RNAs encoding insulin-like growth factor-I prohormones that are differentially glycosylated in vitro. / Bach, Mark A.; Roberts, Charles; Smith, Eric P.; LeRoith, Derek.

In: Molecular Endocrinology, Vol. 4, No. 6, 06.1990, p. 899-904.

Research output: Contribution to journalArticle

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