Experience-dependent decrease in synaptically localized Fra-1.

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• Fos family transcription factors are crucial for long-term neural responses and activity-dependent plasticity.
• Recent findings indicate transcription factors are present in synaptic regions, including dendrites and presynaptic terminals.

Purpose of the Study:

• To investigate the presence and localization of Fos-related antigen-1 (Fra-1) and other Fos proteins within synaptic fractions.
• To explore the role of Fra-1 in synaptic plasticity and its potential communication with the nucleus.

Main Methods:

• Western blotting and immunoelectron microscopy were used to detect and localize Fra-1 and c-Fos in rat brain synaptosomes and synaptic plasma membrane fractions.
• DNA-mobility shift assays assessed AP-1 binding activity in synaptic protein extracts.
• Changes in Fra-1 levels were measured in hippocampal synaptic plasma membranes after inhibitory avoidance training.

Main Results:

• Fra-1 was detected in synaptosome and synaptic plasma membrane fractions, localized to presynaptic plasma membranes.
• Specific AP-1 binding activity was present in synaptic protein extracts.
• Inhibitory avoidance training led to a decrease in Fra-1 levels in hippocampal synaptic plasma membranes, without affecting homogenates, suggesting subcellular redistribution.

Conclusions:

• Fra-1 is present in synaptic regions and associated with presynaptic membranes.
• Fra-1 levels in hippocampal synapses are modulated by learning experiences.
• Fra-1 may be involved in synapse-to-nucleus communication and experience-dependent hippocampal plasticity.