uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
The human insulin mRNA is partly translated via a cap- and eIF4A-independent mechanism
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Cell Biology.
2011 (English)In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 412, no 4, 693-698 p.Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to investigate whether cap-independent insulin mRNA translation occurs in human pancreatic islets at basal conditions, during stimulation at a high glucose concentration and at conditions of nitrosative stress. We also aimed at correlating cap-independent insulin mRNA translation with binding of the IRES trans-acting factor polypyrimidine tract binding protein (FTB) to the 5'-UTR of insulin mRNA. For this purpose, human islets were incubated for 2 h in the presence of low (1.67 mM) or high glucose (16.7 mM). Nitrosative stress was induced by addition of 1 mM DETA/NO and cap-dependent mRNA translation was inhibited with hippuristanol. Insulin biosynthesis rates were determined by radioactive labeling and immunoprecipitation. PTB affinity to insulin mRNA 5'-UTR was assessed by a magnetic micro bead pull-down procedure. We observed that in the presence of 1.67 mM glucose, approximately 70% of the insulin mRNA translation was inhibited by hippuristanol. Corresponding value from islets incubated at 16.7 mM glucose was 93%. DETA/NO treatment significantly decreased the translation of insulin by 85% in high glucose incubated islets, and by 50% at a low glucose concentration. The lowered insulin biosynthesis rates of DETA/NO-exposed islets were further suppressed by hippuristanol with 55% at 16.7 mM glucose but not at 1.67 mM glucose. Thus, hippuristanol-induced inhibition of insulin biosynthesis was less pronounced in DETA/NO-treated islets as compared to control islets. We observed also that PTB bound specifically to the insulin mRNA 5'-UTR in vitro, and that this binding corresponded well with rates of cap-independent insulin biosynthesis at the different conditions. In conclusion, our studies show that insulin biosynthesis is mainly cap-dependent at a high glucose concentration, but that the cap-independent biosynthesis of insulin can constitute as much as 40-100% of all insulin biosynthesis during conditions of nitrosative stress. These data suggest that the pancreatic beta-cell is able to uphold basal insulin synthesis at conditions of starvation and stress via a cap- and eIF4A-independent mechanism, possibly mediated by the binding of FIB to the 5'-UTR of the human insulin mRNA.

Place, publisher, year, edition, pages
2011. Vol. 412, no 4, 693-698 p.
Keyword [en]
Insulin biosynthesis, Polypyrimidine tract binding protein (PTB), Human islets of Langerhans, Nitric oxide, Hippuristanol, Cap-independent translation
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:uu:diva-160157DOI: 10.1016/j.bbrc.2011.08.030ISI: 000295148500033OAI: oai:DiVA.org:uu-160157DiVA: diva2:448478
Available from: 2011-10-17 Created: 2011-10-17 Last updated: 2017-12-08Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Fred, Rikard G.Sandberg, MonicaWelsh, Nils

Search in DiVA

By author/editor
Fred, Rikard G.Sandberg, MonicaWelsh, Nils
By organisation
Department of Medical Cell Biology
In the same journal
Biochemical and Biophysical Research Communications - BBRC
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 638 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf