Authors: Sang S. Seo, Susana R. Louros, Natasha Anstey, Miguel A. Gonzalez-Lozano, Callista B. Harper, Nicholas C. Verity, Owen Dando, Sophie R. Thomson, Jennifer C. Darnell, Peter C. Kind, Ka Wan Li, Emily K. Osterweil
Published: 2022-06-10
DOI: 10.1038/s41467-022-30979-0
Source: Full article
AbstractDysregulated protein synthesis is a core pathogenic mechanism in Fragile X Syndrome (FX). The mGluR Theory of FX predicts that pathological synaptic changes arise from the excessive translation of mRNAs downstream of mGlu1/5 activation. Here, we use a combination of CA1 pyramidal neuron-specific TRAP-seq and proteomics to identify the overtranslating mRNAs supporting exaggerated mGlu1/5 -induced long-term synaptic depression (mGluR-LTD) in the FX mouse model (Fmr1−/y). Our results identify a significant increase in the translation of ribosomal proteins (RPs) upon mGlu1/5 stimulation that coincides with a reduced translation of long mRNAs encoding synaptic proteins. These changes are mimicked and occluded in Fmr1−/y neurons. Inhibiting RP translation significantly impairs mGluR-LTD and prevents the length-dependent shift in the translating population. Together, these results suggest that pathological changes in FX result from a length-dependent alteration in the translating population that is supported by excessive RP translation.