The role of repetitive elements in brain function

Mammalian genomes are comprised of at least 50% of repetitive elements. The vast majority of these sequences originate from retrotransposition of SINE and LINE superfamilies as well as direct transposition of genomic DNA. Full-length LINE transcripts are bicistronic RNAs that provide the machinery for retrotransposition. Retrotransposition events occur during neurogenesis and are part of the normal brain development. Retrotransposons are generally tissue-specific and their expression regulated during development. It is believed that in the human genome there are an average of one million truncated and 5000 full-length LINE sequences with less than one hundred of them able to mobilize in different genomic locations. We are currently investigating the role of the expression and mobilization of retrotransposons in brain function.