Neuronal tRNA modifications in Aplysia californica are repatterned during behavioral habituation

ABSTRACT: Transfer RNA (tRNA) modifications have been increasingly implicated as post-transcriptional regulators of basic neuronal functions. However, characterizing tRNA modification profiles in specific neural circuits that control well-defined behaviors is notoriously difficult due to the complexity of conventional neurobiological models. Here, we leveraged the numerically simple central nervous system (CNS) of the marine mollusk Aplysia californica to investigate tRNA modification dynamics in functionally identified neurons during habituation of a defensive reflex. We identified and quantified dozens of neuronal tRNA modifications using liquid chromatography-tandem mass spectrometry (LC-MS/MS), revealing characteristic distributions of select small RNA modifications across different neuronal and non-neuronal tissues. Upon behavioral habituation of the siphon-elicited siphon withdrawal reflex (SSWR), we found that tRNA modification profiles in the major ganglion that controls the SSWR were repatterned with predictable, learning-related changes. We discovered a family of anticodon loop modifications that changed with habituation learning, including N6-isopentenyladenosine (i6A) which increased in abundance and its downstream product 2-methylthio-N6-isopentenyladenosine (ms2i6A), the levels of which trended downward. These tRNA modification dynamics occurred independently of changes in expression of their parent tRNAs, illustrating that behavioral habituation alters the activity of tRNA-modifying enzymes. Overall, our work reveals an underexplored link between tRNA modifications and behavioral habituation and provides new insights toward understanding the post-transcriptional mechanisms of learning and memory.

INSTRUMENT(S): Liquid Chromatography MS - positive - reverse-phase

PROVIDER: MTBLS15420 | MetaboLights | 2026-09-01

REPOSITORIES: MetaboLights