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Updated: Jun 17, 2026

mirMachine: A One-Stop Shop for Plant miRNA Annotation
06:16

mirMachine: A One-Stop Shop for Plant miRNA Annotation

Published on: May 1, 2021

RNA secondary structural determinants of miRNA precursor processing in Arabidopsis

Liang Song1, Michael J Axtell, Nina V Fedoroff

  • 1The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA.

Current Biology : CB
|December 18, 2009
PubMed

Insights

Plant microRNA (miRNA) processing relies on specific RNA structures. The initial cleavage site is often near an unpaired region, influencing miRNA biogenesis.

Area of Science:

  • Molecular Biology
  • Plant Science
  • RNA Biology

Background:

  • MicroRNAs (miRNAs) are crucial gene regulators derived from primary miRNA (pri-miRNA) hairpin structures.
  • Animal pri-miRNA processing involves two specific cleavage events.
  • Understanding plant pri-miRNA structural determinants is essential for miRNA biogenesis research.

Purpose of the Study:

  • To investigate the RNA structural elements governing pri-miRNA processing in plants.
  • To identify key structural features influencing the rate and location of miRNA precursor cleavage.

Main Methods:

  • Functional analysis of pri-miRNA variants with altered secondary structures (lower, middle, upper stems).
  • Bioinformatic analysis of pri-miRNA structures.
  • Physical mapping of initial cleavage sites.
  • In vitro processing assays of pri-miRNAs.

Main Results:

  • Altering lower stem structure impacts pri-miRNA processing efficiency and mature miRNA abundance.
  • A pri-miRNA with an unpaired lower stem was not processed, indicating its importance.
  • Perfectly paired middle or upper stems did not impede normal processing.
  • The initial loop-distal cleavage is frequently located approximately 15 nt from an unpaired region.

Conclusions:

  • The secondary structure of the pri-miRNA hairpin, particularly the lower stem, is critical for efficient and accurate processing in plants.
  • An imperfectly base-paired duplex of approximately 15 nt near the miRNA:miRNA(*) duplex is a key determinant for the initial pri-miRNA cleavage.
  • These findings provide insights into the mechanism of miRNA biogenesis in plants.

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