RT Journal Article SR Electronic T1 LINE-2 transposable elements shape post-transcriptional gene regulation in the human brain JF bioRxiv FD Cold Spring Harbor Laboratory SP 218842 DO 10.1101/218842 A1 Rebecca Petri A1 Per Ludvik Brattås A1 Marie E Jönsson A1 Karolina Pircs A1 Johan Bengzon A1 Johan Jakobsson YR 2017 UL http://biorxiv.org/content/early/2017/11/13/218842.abstract AB Transposable elements (TEs) are dynamically expressed at high levels in multiple human tissues including the brain, but the function of TE-derived transcripts remains largely unknown. In this study we identify numerous miRNAs that are derived from TEs and expressed in the human brain by conducting AGO2-RIP, followed by small RNA sequencing on human brain tissue. Many of these miRNAs originated from L2 elements, which entered the human genome around 100-300 million years ago. We found that L2-miRNAs derive from the 3’ end of the L2 consensus sequence and that they share very similar sequences, indicating that they could target transcripts with L2s in their 3’UTR. In line with this, we found that many protein-coding genes expressed in the brain carry fragments of L2-derived sequences in the 3’UTR, which serve as target sites for L2-derived miRNAs. Our findings uncover a TE-based post-transcriptional network that shapes transcriptional regulation in the human brain.