Transposable elements (TEs), also called transposons, are DNA sequences that can move or replicate from one location in the genome to another. Although TEs are the most important part of the human genome (approximately 40-50%), scientists have only recently begun to recognize their impact on human diseases ranging from cancer to neurodegenerative diseases.
Normally, our cells keep TEs quiet when they are young, but in a new study from the Boston University Chobanian & Avedian School of Medicine, researchers found that TEs are actively expressed in the human brain as large RNAs that can then be processed into smaller RNAs (18 to 32 nucleotides long). This discovery provides new molecular insights into how our brains age normally and how neurodegenerative diseases affect these normal transposon RNA expression patterns.
Although transposons are normally silenced by our cells’ genomic defense mechanisms, we found that the normal human brain, developing from adolescence to adulthood, naturally expresses larger RNA messages from transposons, and brain cells then metabolize some proportion to smaller RNAs through active or passive mechanisms. ”
Dr. Nelson Lau, Corresponding Author, Associate Professor of Biochemistry and Director of the BU Genome Sciences Institute
Specifically, the researchers investigated how this transposon RNA processing is affected in brain samples from patients with the neurodegenerative diseases Huntington’s disease and Parkinson’s disease. Their results showed that Huntington’s disease affects small RNA expression of transposons, and Parkinson’s disease has an even stronger effect on large RNAs of transposons. Researchers argue that transposon RNA expression deserves more attention in neurodegenerative diseases. This is because our brains continue to express transposon RNAs as we age, and the processing of large RNAs into small RNAs may reveal different origins of neurodegenerative diseases.
Lau and his team designed the study to have access to both publicly available datasets produced by the NIH BrainSpan Atlas consortium and a proprietary dataset created by the groups of Richard Myers and Adam Radolf at Boston University Chobanian & Avedisyan School of Medicine. These human brain RNA datasets are specialized to include matched sets of both large and small RNAs sequenced from each human sample. The BU team then integrated all these datasets into a complex bioinformatics analysis platform to examine trends in changes in transposon RNA levels.
Researchers say Huntington’s disease has a clear genetic cause, but the genetic cause of Parkinson’s disease remains unclear. “We asked whether the expression of transposon RNAs in these two disease states could shed light on the molecular differences between these two diseases. Most studies have ignored transposon RNAs, so we wanted to refocus on these more difficult transcripts to understand how the brain expresses, metabolizes, and processes these RNAs during aging,” added Lau.
The findings will be published in the online journal Genome Research.
sauce:
Boston University School of Medicine
Reference magazines:
Dayama, G. others. (2026). Small and large RNAs of transposable elements in the aging brain and their impact on Huntington’s and Parkinson’s diseases. genome research. DOI: 10.1101/gr.280565.125. https://genome.cshlp.org/content/early/2026/05/18/gr280565125
