Transposition-driven genomic heterogeneity in the Drosophila brain

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Mammalian studies suggest neural genomes are dynamic mosaics due to retrotransposon activity.
• Retrotransposons, mobile genetic elements, can alter genome structure and function.

Purpose of the Study:

• To investigate retrotransposon transposition in the Drosophila brain, particularly in memory-relevant neurons.
• To explore the relationship between transposon expression, Piwi-interacting RNAs (piRNAs), and neuronal genomic diversity.

Main Methods:

• Cell type-specific gene expression profiling in Drosophila.
• Analysis of Piwi-interacting RNA (piRNA) protein abundance in brain tissues.
• Paired-end deep sequencing to identify de novo transposon insertions.

Main Results:

• Retrotransposon transposition was confirmed in memory-relevant neurons (mushroom body αβ neurons) in the Drosophila brain.
• Transposon expression was higher in αβ neurons compared to other mushroom body neurons.
• Reduced abundance of piRNA proteins (Aubergine, Argonaute 3) correlated with increased transposon expression.
• Over 200 de novo transposon insertions were identified in αβ neurons, some within memory-associated genes.

Conclusions:

• Genomic heterogeneity generated by retrotransposon activity is a conserved feature of neuronal genomes.
• The piRNA pathway plays a role in suppressing transposon mobility in the fly brain.
• Neuronal activity and genomic plasticity are linked, potentially impacting memory formation.