Transposons

Alzheimer’s Progression Link: Recent research from UT Health San Antonio suggests that the activation of “jumping genes” (transposons) may play a significant role in the progression of Alzheimer’s disease.

What are Jumping Genes? Also known as transposons, these are mobile genetic elements that can move within the genome. They make up almost 50% of the human genome. Most are inactive, but some can “jump,” leading to genomic instability.

LINE-1 Retrotransposons: A common type, these replicate through RNA and use reverse transcriptase to integrate into DNA. Their activity is normally controlled, but these controls can weaken in aging or diseased brains.

Mechanism of Damage: When activated, transposons can insert into essential genes, disrupting DNA and causing cellular damage, particularly in vulnerable neurons.

Fruit Fly Experiments: Blocking transposon activity in fruit flies mimicking Alzheimer’s symptoms using an HIV drug (3TC) improved neural function. 3TC is a reverse transcriptase inhibitor, preventing retrotransposon copying.

Human Clinical Trial: While 3TC didn’t directly improve memory in human patients, it reduced neurofilament light (NfL), a marker of neurodegeneration, suggesting neuronal protection.

New Alzheimer’s Hypothesis: Alzheimer’s may be caused by genomic instability from jumping genes, not just protein aggregation (amyloid or tau).

Barbara McClintock Discovery: Jumping genes were discovered by Barbara McClintock, who won the Nobel Prize in 1983 for her work.

Impact on Evolution: Jumping genes contribute to genetic diversity, genome reorganization, and can sometimes trigger diseases by disrupting normal gene function.