Transposition driven genomic heterogeneity in the Drosophila brain. Drosophila melanogaster

Recent studies in mammals have documented neural expression and mobility of retrotransposons and suggested that neural genomes are diverse mosaics. Here we report transposition in memory-relevant neurons in the Drosophila brain. Cell-type specific gene expression profiling revealed transposon expression is more abundant in mushroom body (MB) αβ neuronsthan in neighboring MB neurons. The PIWI-RNA (piRNA) proteins Aubergine and Argonaute 3, known to suppress transposons in the fly germline, are expressed in the brain and appear less abundant in αβ MB neurons. Importantly loss of piRNA proteins correlates with elevated transposon expression in brain. Lastly, paired-end deep sequencing identified over 200 de novo transposon insertions in αβ neurons, including events into memory-relevant loci. Our observations indicate that genomic heterogeneity is a conserved feature of the brain.