Related Experiment Video
Updated: Aug 18, 2026
Preparation of Synaptoneurosomes from Mouse Cortex using a Discontinuous Percoll-Sucrose Density Gradient
Published on: September 17, 2011
The isolation, from electromotor neurone perikarya, of messenger RNAs coding for synaptic proteins
Abstract:
Poly(A)-containing mRNA was isolated from the electric lobe, cerebellum and forebrain of Torpedo marmorata and from cholinergic electromotor perikarya isolated from the electric lobe. All the mRNA preparations were translated by a cell-free protein-synthesizing system from rabbit reticulocytes; no brain-specific factors were required. The highest stimulation rate was found with the perikaryal mRNA suggesting that this purely neuronal mRNA is a preferred template in the protein-synthesis system; the molecular basis of this phenomenon remains to be elucidated. The translation products of the perikaryal mRNA were analysed by two-dimensional gel electrophoresis and compared with the proteins of synaptosomes derived from the electromotor nerve terminals. The majority of the synaptosomal proteins comigrated with synthesized products. More than 100 synthesized proteins were detected as individual spots in the gel pattern, among them actin, subunits of neurofilamentous proteins and a protein considered to be a specific component of electromotor synaptic vesicles. Identities were confirmed in some cases by immunochemical methods. The results suggest that protein synthesis in the perikaryon of the electromotor neurone is largely directed to the production of proteins needed to maintain synaptic integrity. A comparison of the translation products of mRNA derived from the highly cholinergic electric lobe and a brain region, the cerebellum, which is non-cholinergic, revealed, as expected, some common translation products and others which appeared to be specific for the brain regions concerned. This approach may lead to the identification of protein specific for neurones of different transmitter types.
Insights
Messenger RNA (mRNA) from Torpedo electric eel neurons was translated in a cell-free system. This revealed proteins crucial for synaptic function and identified potential neuron-specific proteins.
Area of Science:
- Neuroscience
- Molecular Biology
- Biochemistry
Background:
- Messenger RNA (mRNA) isolation and translation are key techniques for understanding neuronal protein synthesis.
- Cholinergic neurons, like those in the electric lobe, have unique protein requirements for neurotransmission.
Purpose of the Study:
- To investigate the protein synthesis profile of cholinergic electromotor neurons in Torpedo marmorata.
- To identify proteins synthesized by neuronal mRNA and compare them to synaptic proteins.
- To explore the potential for identifying neuron-specific proteins through mRNA translation.
Main Methods:
- Isolation of poly(A)-containing mRNA from Torpedo electric lobe, cerebellum, and forebrain.
- Cell-free translation of mRNA using a rabbit reticulocyte system.
- Two-dimensional gel electrophoresis to analyze translation products.
- Comparison of synthesized proteins with synaptosomal proteins using gel electrophoresis and immunochemical methods.
Main Results:
- Neuronal mRNA from Torpedo electric eel brain regions could be translated without brain-specific factors.
- Perikaryal mRNA showed the highest translation rate, suggesting it's a preferred template.
- Over 100 proteins were synthesized, including actin, neurofilament subunits, and a specific synaptic vesicle protein.
- A majority of synaptosomal proteins comigrated with synthesized products, indicating efficient protein synthesis for synaptic maintenance.
- Differences in translation products were observed between cholinergic (electric lobe) and non-cholinergic (cerebellum) brain regions.
Conclusions:
- Protein synthesis in electromotor neuron perikarya is primarily directed towards maintaining synaptic integrity.
- The study successfully identified numerous neuronal proteins and suggests a method for discovering proteins specific to different neuron types.
- Further research is needed to elucidate the molecular basis for the high translation efficiency of perikaryal mRNA.
Related Concept Videos
01:12Synaptic Signaling
02:47The Synapse
02:31Nuclear Export of mRNA
01:09Synaptic Signaling
Most synapses are chemical, meaning an electrical impulse or action potential spurs the release of chemical messengers called neurotransmitters. The neuron sending the signal is called the presynaptic neuron, and the neuron receiving the signal is the postsynaptic neuron.
The presynaptic neuron fires an action potential that...
01:26Chemical Synapses
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
01:28Neuronal Communication