Dynamical Mechanisms for Gene Regulation Mediated by Two Noncoding RNAs in Long-Term Memory Formation

Area of Science:

• Neuroscience
• Molecular Biology
• Systems Biology

Background:

• Noncoding RNAs, including microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs), are crucial regulators of gene expression underlying long-term synaptic plasticity and memory.
• Serotonin (5-HT) signaling plays a key role in modulating these noncoding RNAs and epigenetic modifications.

Purpose of the Study:

• To investigate the regulatory roles of specific noncoding RNAs (miR-124 and piR-F) in long-term memory formation in Aplysia.
• To model the gene regulatory network involving 5-HT, noncoding RNAs, and key memory-associated genes (CREB1, CREB2).
• To explore the dynamical properties and epigenetic mechanisms of long-term memory formation.

Main Methods:

• Development of a gene regulatory network motif model incorporating miR-124 and piR-F.
• Application of codimension-1 and -2 bifurcation analyses to study system dynamics under 5-HT stimulation.
• Experimental verification of model predictions using three 5-HT stimulus protocols in Aplysia.
• Bifurcation analyses of noncoding RNA concentrations to understand epigenetic regulation.

Main Results:

• The model predicts bistability and oscillations in gene expression, robust to parameter variations.
• Experimental results confirm that specific 5-HT pulse patterns transiently alter miR-124 and piR-F levels.
• A five-pulse 5-HT stimulus protocol leads to sustained high CREB1 levels, a marker for long-term memory.

Conclusions:

• Noncoding RNAs and epigenetic modifications mediated by 5-HT are critical for establishing long-term memory.
• The study elucidates the dynamical mechanisms by which noncoding RNAs contribute to synaptic plasticity and memory.
• This research provides insights into the interplay between noncoding RNAs, epigenetic regulation, and memory consolidation.