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Measurement of Poly A Tail Length from Drosophila Larva Brain and Cell Line
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Control of poly(A) polymerase level is essential to cytoplasmic polyadenylation and early development in Drosophila

François Juge1, Sophie Zaessinger, Claudia Temme

  • 1Génétique du Développement de la Drosophile, Institut de Génétique Humaine, 141 rue de la Cardonille, 34396 Montpellier Cedex 5, France.

The EMBO Journal
|November 29, 2002
PubMed

Insights

A single Poly(A) polymerase (PAP) in Drosophila regulates both nuclear and cytoplasmic polyadenylation. Its precise regulation is crucial for development, as overexpression causes embryonic lethality due to uncontrolled cytoplasmic polyadenylation.

Area of Science:

  • Molecular Biology
  • Developmental Biology
  • Genetics

Background:

  • Poly(A) polymerase (PAP) is vital for mRNA processing, involved in nuclear polyadenylation and cytoplasmic polyadenylation for translational control.
  • Mammals possess multiple PAP genes encoding various isoforms, but their specific in vivo functions remain unclear.
  • Understanding PAP function is critical for comprehending gene expression regulation during development.

Purpose of the Study:

  • To investigate the function and regulation of Poly(A) polymerase (PAP) in Drosophila.
  • To determine if a single PAP isoform can mediate both nuclear and cytoplasmic polyadenylation in vivo.
  • To elucidate the role of PAP levels in controlling poly(A) tail length and developmental outcomes.

Main Methods:

  • Analysis of PAP gene and isoform expression in Drosophila.
  • In vitro activity assays for Drosophila PAP.
  • In vivo studies involving PAP overexpression in Drosophila embryos.
  • Assessment of poly(A) tail lengths in nuclear and cytoplasmic fractions.
  • Evaluation of developmental consequences, including embryonic lethality.

Main Results:

  • Drosophila possesses a single PAP isoform, encoded by the hiiragi gene.
  • This single PAP isoform is active in vitro and participates in both nuclear and cytoplasmic polyadenylation in vivo.
  • Overexpression of PAP in vivo did not alter nuclear polyadenylation but caused dramatic poly(A) tail elongation and loss of specificity in cytoplasmic polyadenylation.
  • PAP overexpression resulted in embryonic lethality, highlighting the critical role of its regulation.

Conclusions:

  • A single PAP isoform in Drosophila is sufficient to perform both nuclear and cytoplasmic polyadenylation.
  • Regulation of PAP levels is essential for precise control of cytoplasmic polyadenylation.
  • Controlled cytoplasmic polyadenylation by PAP is critical for successful early development in Drosophila.

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