Repeat-element RNAs integrate a neuronal growth circuit.

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Neuronal growth and regeneration depend on local mRNA translation within axons.
• Understanding the molecular mechanisms regulating axonal repair is critical for treating neurological injuries.

Purpose of the Study:

• To investigate changes in RNA polyadenylation following sensory neuron injury.
• To identify novel elements involved in regulating axonal regeneration.

Main Methods:

• Analysis of RNA polyadenylation in injured sensory neurons.
• Induction and expression of B2-SINE repeat elements (GI-SINEs).
• Assessment of axonal growth in various neuronal models (sensory, retinal, corticospinal).
• Investigation of GI-SINE interactions with ribosomal proteins and nucleolin.
• Use of antisense oligonucleotides to disrupt GI-SINE function.

Main Results:

• Upregulation of specific polyadenylated B2-SINE repeat elements (GI-SINEs) in injured sensory neurons.
• GI-SINEs are induced from AP-1 promoter-associated loci.
• Exogenous GI-SINE expression promotes axonal growth in multiple neuronal types.
• GI-SINEs interact with ribosomal proteins and nucleolin to modulate cytoplasmic translation.
• Antisense inhibition of GI-SINEs impairs sensory neuron outgrowth and nucleolin-ribosome interactions.

Conclusions:

• A specific subfamily of transposable elements, GI-SINEs, plays an integral role in neuronal regeneration.
• GI-SINEs bridge AP-1 transcription factors with localized RNA translation machinery in neurons.
• These findings reveal a novel regulatory circuit for axonal growth and repair.