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Updated: Jul 15, 2026

Polysome Fractionation and Analysis of Mammalian Translatomes on a Genome-wide Scale
10:56

Polysome Fractionation and Analysis of Mammalian Translatomes on a Genome-wide Scale

Published on: May 17, 2014

MicroRNAs, mRNAs, and translation

P A Maroney1, Y Yu, T W Nilsen

  • 1Center for RNA Molecular Biology and Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4973, USA.

Cold Spring Harbor Symposia on Quantitative Biology
|March 27, 2007
PubMed

Insights

MicroRNAs (miRNAs) are regulatory molecules impacting gene expression. This study found most miRNAs associate with translating mRNAs in polysomes, suggesting a role in translation regulation.

Area of Science:

  • Molecular Biology
  • Gene Regulation
  • Cell Biology

Background:

  • MicroRNAs (miRNAs) are key regulators of gene expression in animal cells, primarily by repressing protein production from target messenger RNAs (mRNAs).
  • Despite their widespread influence, the precise mechanisms underlying miRNA function remain incompletely understood.
  • Investigating the subcellular localization of miRNAs is crucial for elucidating their mode of action.

Purpose of the Study:

  • To investigate the subcellular distribution of microRNAs (miRNAs) in actively growing HeLa cells.
  • To determine the association of miRNAs with actively translating messenger RNAs (mRNAs).
  • To explore the impact of miRNA association on mRNA translation, specifically focusing on KRAS mRNA.

Main Methods:

  • Analysis of subcellular localization of miRNAs in HeLa cells.
  • Identification of miRNA association with polysomal fractions containing actively translating mRNAs.
  • Examination of KRAS mRNA association with polysomes and its translational status.

Main Results:

  • The vast majority of analyzed miRNAs were found to be associated with actively translating mRNAs within polysomes.
  • A specific miRNA-regulated mRNA, KRAS, was also found to be polysome-associated.
  • Translation of the KRAS mRNA appeared to be impaired, potentially at the elongation stage, in the presence of miRNA regulation.

Conclusions:

  • MicroRNA (miRNA) localization within polysomes suggests a direct role in regulating the translation of associated messenger RNAs (mRNAs).
  • The observed impairment of KRAS mRNA translation indicates that miRNAs may influence translation elongation.
  • These findings contribute to a deeper understanding of the mechanistic basis of miRNA-mediated gene regulation.

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