Related Experiment Video
Updated: May 19, 2026
08:30
Preparation of Synaptoneurosomes from Mouse Cortex using a Discontinuous Percoll-Sucrose Density Gradient
Published on: September 17, 2011
Primary microRNA precursor transcripts are localized at post-synaptic densities in adult mouse forebrain
Giovanni Lugli1, John Larson, Michael P Demars
1Department of Psychiatry and Psychiatric Institute, University of Illinois at Chicago, Chicago, IL 60612, USA.
Journal of Neurochemistry
|August 18, 2012
Summary
Primary microRNA gene transcripts (pri-miRs) are found at synapses, not just their precursors. This suggests microRNA biogenesis occurs locally near synapses, impacting neuronal function.
Area of Science:
- Neuroscience
- Molecular Biology
- Genetics
Background:
- Previous studies detected microRNA (miRNA) precursors in synaptic fractions, but couldn't differentiate between primary microRNA gene transcripts (pri-miRs) and hairpin precursors (pre-miRs).
- Distinguishing between pri-miRs and pre-miRs is crucial for understanding miRNA biogenesis location and regulation.
Purpose of the Study:
- To determine the presence and localization of pri-miRs within synaptic fractions and post-synaptic densities (PSDs).
- To investigate the association of key miRNA biogenesis proteins, Drosha and DGCR8, with pri-miRs at synapses.
- To explore the potential transport mechanisms of pri-miRs to synaptic regions.
Main Methods:
- Utilized specific qRT-PCR primers to distinguish pri-miRs from pre-miRs in isolated synaptic fractions and PSDs.
- Employed co-immunoprecipitation to assess the association between pri-miRs, Drosha, and DGCR8 under stringent conditions.
- Analyzed fractions containing mRNA transport particles and investigated the association of Drosha with kinesin heavy chain.
Main Results:
- Demonstrated significant enrichment of pri-miRs in synaptic fractions and even greater enrichment in isolated PSDs.
- Confirmed the presence and tight association of Drosha and DGCR8 proteins with pri-miRs in synaptic fractions and PSDs.
- Found pri-miRs, Drosha, and DGCR8 co-localized with mRNA transport particles, and Drosha associated with kinesin, suggesting active transport.
Conclusions:
- Pri-miRs, along with essential biogenesis machinery (Drosha, DGCR8), are actively transported to and present at synapses.
- This synaptic localization and association support the model of local miRNA biogenesis occurring near synapses.
- Findings indicate a regulated, local mechanism for miRNA production influencing synaptic function.
