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Alternative polyadenylation of the amyloid protein precursor mRNA regulates translation

F de Sauvage1, V Kruys, O Marinx

  • 1Laboratoire de Neurochimie, Université Catholique de Louvain, Bruxelles, Belgium.

The EMBO Journal
|August 1, 1992
PubMed

Insights

Two polyadenylation sites in amyloid precursor protein mRNA influence protein production. A specific sequence within these sites enhances translation efficiency, not mRNA stability, impacting protein levels in brain cells.

Area of Science:

  • Molecular Biology
  • Neuroscience
  • Genetics

Background:

  • Amyloid protein precursor (APP) is central to Alzheimer's disease research.
  • Differential mRNA processing can lead to distinct protein isoforms.
  • Understanding mRNA regulation is crucial for cellular function.

Purpose of the Study:

  • To investigate the functional impact of alternative polyadenylation sites in APP mRNA.
  • To determine if differences in APP mRNA length affect protein production.
  • To identify regulatory elements within the 3' untranslated region of APP mRNA.

Main Methods:

  • RNA blot analysis to identify mRNA variants.
  • In vitro transcription and translation in Xenopus oocytes.
  • Construction and transfection of chimeric cDNAs in Chinese hamster ovary cells.

Main Results:

  • Two major APP mRNA variants (3.2 and 3.4 kb) were identified, differing in polyadenylation sites.
  • Longer APP mRNA (3.4 kb) produced significantly more protein than shorter mRNA (3.2 kb).
  • A sequence within the alternative polyadenylation region enhanced translation of heterologous reporter genes (lysozyme, CAT).

Conclusions:

  • Alternative polyadenylation in APP mRNA directly influences protein yield.
  • A specific sequence element within the 3' untranslated region enhances mRNA translation, independent of mRNA stability.
  • This finding provides insight into post-transcriptional regulation of APP and potentially other genes.

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