{"id":187632,"date":"2025-08-30T17:03:22","date_gmt":"2025-08-30T17:03:22","guid":{"rendered":"https:\/\/www.europesays.com\/us\/187632\/"},"modified":"2025-08-30T17:03:22","modified_gmt":"2025-08-30T17:03:22","slug":"junk-dna-plays-key-role-in-brain-development-and-disease","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/187632\/","title":{"rendered":"\u201cJunk DNA\u201d Plays Key Role in Brain Development and Disease"},"content":{"rendered":"<p><strong>Summary: <\/strong>A new study shows that repetitive DNA, once dismissed as \u201cjunk,\u201d plays a critical role in shaping the human brain. Scientists found that LINE-1 transposons, a type of mobile DNA element, are active in stem cells and regulate key genes during early brain development.<\/p>\n<p>When these sequences were switched off, brain organoids grew abnormally, suggesting their influence on both evolution and disease. The findings reveal that hidden parts of the genome could be central to understanding conditions like Parkinson\u2019s and neurodevelopmental disorders.<\/p>\n<p><strong>Key Facts<\/strong><\/p>\n<ul class=\"wp-block-list\">\n<li><strong>Hidden Regulators:<\/strong> LINE-1 transposons in non-coding DNA guide brain development.<\/li>\n<li><strong>Consequences of Silence:<\/strong> Blocking them disrupted growth in lab-grown brain organoids.<\/li>\n<li><strong>Disease Connection:<\/strong> Many affected genes are tied to neurodevelopmental and psychiatric disorders.<\/li>\n<\/ul>\n<p><strong>Source: <\/strong>Lund University<\/p>\n<p><strong>For decades, large stretches of human DNA were dismissed as \u201cjunk,\u201d thought to serve no real purpose.<\/strong><\/p>\n<p>In a new study in Cell Genomics, researchers at Lund University show that the repetitive part of the human genome plays an active role during early brain development and may also be relevant for understanding brain diseases.<\/p>\n<p>DNA carries the complete set of instructions an organism needs to develop and survive, but only about 1.5% of it consists of protein-coding genes that determine traits such as eye color, height, and hair type.<\/p>\n<p>  <img fetchpriority=\"high\" decoding=\"async\" width=\"1200\" height=\"800\" src=\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2025\/08\/junk-dna-neurodevelopment-neurosience.jpg\" alt=\"This shows a brain and DNA.\"  \/> With many of the genes affected by L1 transposons linked to brain disorders, their work opens new avenues for future research. Credit: Neuroscience News<\/p>\n<p>The other 98.5%, once written off as \u2018junk DNA,\u2019 is now recognized more and more as an important part of our genome that controls when and where genes are switched on, influencing development, cellular processes, and even human evolution.<\/p>\n<p>At Lund University, researchers have been exploring this overlooked portion of the genome. Their latest study published in Cell Genomics shows how specific sequences within the non-coding genome help shape the developing human brain.<\/p>\n<p>\u201cAn underlying question in my lab is: how did the human brain become human?\u201d says Johan Jakobsson, Professor in the Department of Experimental Medical Sciences, and head of the Laboratory of Molecular Neurogenetics.<\/p>\n<p>\u201cWe want to know which parts of the genome contribute to uniquely human functions, and how this connects to brain disorders.\u201d<\/p>\n<p>Repetitive DNA has an active role in the human brain<\/p>\n<p>In the new study, Johan Jakobsson and his team, together with collaborators at the University of Copenhagen, the University of Cambridge, and New York University, investigated segments of repetitive DNA sequences called transposable elements. Sometimes described as \u201cjumping genes,\u201d these sequences can move around within the genome, making them challenging to study.<\/p>\n<p>Using induced pluripotent stem cells and brain organoids, miniature, simplified versions of the human brain grown in the lab, the researchers studied one particular family of transposable elements, known as LINE-1 (L1) transposons. By combining CRISPR gene-editing technology with advanced sequencing methods, they were able to switch these sequences off and observe the effects.<\/p>\n<p>\u201cPreviously we assumed this part of the genome was switched off and just sitting quietly in the background,\u201d Johan Jakobsson says.<\/p>\n<p>\u201cIt turns out that\u2019s a misconception. These elements are not silent; they are active in human stem cells and seem to play an important role in early brain development. And we found that when you block them, there are real consequences.\u201d<\/p>\n<p>Jumping genes effect on brain development<\/p>\n<p>When the L1 transposons were silenced, the team observed disruptions in gene activity and abnormal brain organoid growth.<\/p>\n<p>\u201cFrom an evolutionary perspective, this could help explain how the human brain developed differently from that of other primates,\u201d Johan Jakobsson notes.<\/p>\n<p>\u201cBut from a disease perspective, it also tells us that these elements are part of the cell\u2019s machinery and probably linked to disorders. If we want to fully understand neurodevelopmental disorders or neuropsychiatric conditions, we have to study this part of the genome.\u201d<\/p>\n<p>With many of the genes affected by L1 transposons linked to brain disorders, their work opens new avenues for future research.<\/p>\n<p>How does the non-coding genome contribute to brain disease?<\/p>\n<p>The Lund team is continuing this work through the ASAP (Aligning Science Across Parkinson\u2019s) Collaborative Research Network, working with international partners to investigate how transposable elements contribute to brain diseases using both patient-derived cells and donated brain tissue samples.<\/p>\n<p>\u201cThis study points to the fact that these elements are not just evolutionary leftovers, they are important for regulating genes that are active in the brain,\u201d Johan Jakobsson concludes.<\/p>\n<p>\u201cOur next step is to investigate patient samples, from children with neurodevelopmental disorders and adults with age-related conditions such as Parkinson\u2019s disease. The goal is to understand how these hidden parts of our genome contribute to disease and, eventually, how we might use that knowledge to improve treatments.\u201d<\/p>\n<p>About this genetics, neurodevelopment, and neurology research news<\/p>\n<p class=\"has-background\" style=\"background-color:#ffffe8\"><strong>Author: <\/strong><a href=\"http:\/\/neurosciencenews.com\/cdn-cgi\/l\/email-protection#ee8f80808fc0868b8282899c8b80ae838b8ac0829bc09d8b\" target=\"_blank\" rel=\"noreferrer noopener\">Anna Elizabeth Hellgren<\/a><br \/><strong>Source: <\/strong><a href=\"https:\/\/med.lu.se\" target=\"_blank\" rel=\"noreferrer noopener\">Lund University<\/a><br \/><strong>Contact: <\/strong>Anna Elizabeth Hellgren \u2013 Lund University<br \/><strong>Image: <\/strong>The image is credited to Neurosciene News<\/p>\n<p class=\"has-background\" style=\"background-color:#ffffe8\"><strong>Original Research: <\/strong>Open access.<br \/>\u201c<a href=\"https:\/\/dx.doi.org\/10.1016\/j.xgen.2025.100979\" target=\"_blank\" rel=\"noreferrer noopener\">LINE-1 retrotransposons mediate cis-acting transcriptional control in human pluripotent stem cells and regulate early brain development<\/a>\u201d by Johan Jakobsson et al. Cell Genomics<\/p>\n<p><strong>Abstract<\/strong><\/p>\n<p><strong>LINE-1 retrotransposons mediate cis-acting transcriptional control in human pluripotent stem cells and regulate early brain development<\/strong><\/p>\n<p>Long interspersed nuclear element 1 (L1) retrotransposons represent a vast source of genetic variability.<\/p>\n<p>However, mechanistic analysis of whether and how L1s contribute to human developmental programs is lacking, in part due to the challenges associated with specific profiling and manipulation of human L1 expression.<\/p>\n<p>Here, we show that thousands of hominoid-specific L1 integrants are expressed in human induced pluripotent stem cells and cerebral organoids.<\/p>\n<p>The activity levels of individual L1 promoters vary widely and correlate with an active epigenetic state.<\/p>\n<p>Efficient on-target CRISPR interference (CRISPRi) silencing of L1s revealed nearly a hundred co-opted L1-derived chimeric transcripts, and L1 silencing resulted in changes in neural differentiation programs and reduced cerebral organoid size.<\/p>\n<p>Together, these data implicate L1s and L1-derived transcripts in hominoid-specific CNS developmental processes.<\/p>\n","protected":false},"excerpt":{"rendered":"Summary: A new study shows that repetitive DNA, once dismissed as \u201cjunk,\u201d plays a critical role in shaping&hellip;\n","protected":false},"author":3,"featured_media":187639,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[826,827,828,815,98278,105099,105100,829,830,831,159,67,132,68],"class_list":{"0":"post-187632","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-genetics","8":"tag-brain-development","9":"tag-brain-research","10":"tag-developmental-neuroscience","11":"tag-genetics","12":"tag-junk-dna","13":"tag-line-1","14":"tag-lund-university","15":"tag-neurobiology","16":"tag-neurodevelopment","17":"tag-neuroscience","18":"tag-science","19":"tag-united-states","20":"tag-unitedstates","21":"tag-us"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/115118801019856838","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/187632","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=187632"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/187632\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/187639"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=187632"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=187632"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=187632"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}