Alzheimer’s-linked protein fibres found carrying genetic messages into sperm
Proteins best known for their role in Alzheimer’s disease may have a useful job in reproduction, scientists at Columbia University have found. Amyloid fibrils — tiny protein fibres found in semen — can pick up RNA molecules, carry them into sperm cells, and deliver them to an embryo after fertilisation, according to research published in the journal Molecular Cell.
The work, led by William Mallen and Anthony Fitzpatrick at Columbia’s Zuckerman Institute, started with a clue from HIV. Earlier research showed that amyloid fibrils in semen can help HIV enter cells in the reproductive tract. Since HIV carries its genetic information as RNA, the team wondered whether the fibres could also carry the body’s own RNA. They can: amyloids are positively charged and RNA is negatively charged, so the two bind together.
Using cryo-electron tomography, which images frozen samples in 3D, the team found gold-labelled amyloid fibres inside sperm cells — proof that they cross the cell boundary rather than just sticking to the surface. In laboratory fertilisation experiments, sperm carrying amyloid-bound RNA for a green fluorescent protein produced embryos with at least 10 times more of that protein than embryos fertilised with sperm given the same RNA without amyloids. The fibres may also protect fragile RNA in transit, though that is unproven.
Why it matters
It could help explain how RNA from seminal fluid reaches sperm and influences the embryo. Earlier research suggests sperm-carried RNA can switch genes on or off in offspring, and mouse studies have linked paternal transmission of conditions such as insulin resistance to RNA. Understanding that delivery could help treat or prevent disorders passed down through epigenetics — changes in how genes are used, without altering DNA.
It may also have medical uses. Gene-editing tools such as CRISPR rely on RNA, but delivering it into cells is hard, and the modified viruses often used can trigger immune reactions. Human-based amyloid fibrils might one day offer another route, though their safety and effectiveness are untested.
What happens next
Much remains unknown, including what amyloid-carried RNA does inside sperm in the body, and whether the route works the same way outside the laboratory. Next, they plan to study what the transported RNA does in the embryo and test whether amyloid fibrils can safely carry therapeutic RNA into cells.
This article is for general information and education only. It is not legal or financial advice.
Sources
- https://scitechdaily.com/alzheimers-linked-proteins-have-a-hidden-role-in-human-reproduction/ (SciTechDaily, 31 Oct 2026)
- https://phys.org/news/2026-10-protein-fibers-hallmark-alzheimer-genetic.html (Phys.org, 26 Oct 2026)
