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Updated: Sep 20, 2025

A Robust Polymerase Chain Reaction-based Assay for Quantifying Cytosine-guanine-guanine Trinucleotide Repeats in Fragile X Mental Retardation-1 Gene
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A Robust Polymerase Chain Reaction-based Assay for Quantifying Cytosine-guanine-guanine Trinucleotide Repeats in Fragile X Mental Retardation-1 Gene

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Excess ribosomal protein production unbalances translation in a model of Fragile X Syndrome

Sang S Seo1,2, Susana R Louros1,2, Natasha Anstey1,2

  • 1Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.

Nature Communications
|June 10, 2022
PubMed

Insights

Fragile X Syndrome involves protein synthesis issues. Excessive translation of ribosomal proteins, not synaptic proteins, drives pathological changes in Fragile X Syndrome, impacting synaptic plasticity.

Area of Science:

  • Neuroscience
  • Molecular Biology
  • Genetics

Background:

  • Dysregulated protein synthesis is a key factor in Fragile X Syndrome (FX).
  • The metabotropic glutamate receptor (mGluR) theory of FX suggests excessive mRNA translation downstream of mGluR5 activation causes synaptic pathology.
  • Fragile X Syndrome is a genetic disorder causing intellectual disability and developmental issues.

Purpose of the Study:

  • To identify specific mRNAs that are excessively translated following mGluR5 activation in Fragile X Syndrome.
  • To investigate the role of ribosomal protein (RP) translation in mGluR5-dependent synaptic changes in FX.
  • To understand the length-dependent regulation of mRNA translation in FX.

Main Methods:

  • Utilized CA1 pyramidal neuron-specific TRAP-seq and proteomics in a mouse model of Fragile X Syndrome (Fmr1-/y).
  • Measured mRNA translation changes upon mGluR5 stimulation.
  • Assessed the impact of inhibiting RP translation on mGluR-LTD and mRNA translation patterns.

Main Results:

  • Identified a significant increase in the translation of ribosomal proteins (RPs) upon mGluR5 stimulation in FX models.
  • Observed a concurrent decrease in the translation of long mRNAs encoding synaptic proteins.
  • Found that inhibiting RP translation ameliorates mGluR-LTD and normalizes the translation of length-dependent mRNA populations.

Conclusions:

  • Pathological synaptic changes in Fragile X Syndrome are driven by excessive RP translation, leading to a shift in the translating mRNA population.
  • These findings support a length-dependent alteration in mRNA translation as a core mechanism in FX pathogenesis.
  • Targeting RP translation may offer a therapeutic strategy for Fragile X Syndrome.

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