Accumulating extra genome copies may protect fly brain cells during
aging
To prevent cell death caused by DNA damage, adult brain cells in fruit
flies produce extra copies of their chromosomes

Date:
August 25, 2020
Source:
eLife
Summary:
Scientists have discovered a novel anti-aging defense in the brain
cells of adult fruit flies: producing extra copies of the genome,
according to a new study.



FULL STORY ========================================================================== Scientists have discovered a novel anti-aging defence in the brain cells
of adult fruit flies: producing extra copies of the genome, according
to a new study published today in eLife.


==========================================================================
The findings could help explain how the brain, which rarely produces new
cells, is able to cope with the accumulation of cell damage over time
and prevent excess cell loss during aging. They may also help scientists
answer questions about human age-related brain diseases.

Most cells have two copies of each chromosome, one from each parent. This provides each cell with two complete copies of DNA, referred to as
the genome.

But some cells accumulate extra copies of chromosomes, although how and
why they do this is not entirely clear. Some scientists have suggested
that excess chromosomes might lead to age-related brain diseases.

"The brain of the fruit fly Drosophila melanogaster is an ideal model
for studying age-related changes in the brain because the fly has a
relatively short lifespan, its brain cells rarely multiply, and we have excellent tools for manipulating fly genetics," says lead author Shyama Nandakumar, a doctoral student in the department of Molecular, Cellular,
and Developmental Biology at the University of Michigan, Ann Arbor, US.

In the study, Nandakumar and colleagues examined adult fly brain cells
and found that some accumulate extra copies of their genome, especially
in parts of the brain responsible for vision -- the region of the brain
which shows more DNA damage with age.

Next, they subjected fly brain cells to oxidative stress or ultraviolet radiation, which damage DNA and can cause cell death. They found that
this exposure increased the production of extra copies of chromosomes
in the cells, and the cells were less likely to die as a result of the
damage. "These data suggest that cells with extra copies of the genome
are more resistant to cell death and may serve a beneficial or protective
role in the aging brain," Nandakumar explains.

Previous studies have found that patients with early stages of Alzheimer's disease have extra chromosomes in their brain cells than people of
the same age who do not have the condition. This has led scientists
to question whether accumulating extra chromosomes leads to brain cell
death and brain disease.

"Our study suggests that the production of extra copies of chromosomes
might actually be a normal response to the accumulation of age-related
damage in flies and may even help protect against cell death," concludes
senior author Laura Buttitta, Associate Professor of Molecular, Cellular
and Developmental Biology at the University of Michigan. "Further studies
are now needed to determine if this is also true in humans."

========================================================================== Story Source: Materials provided by eLife. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Shyama Nandakumar, Olga Grushko, Laura A Buttitta. Polyploidy in the
adult Drosophila brain. eLife, 2020; 9 DOI: 10.7554/eLife.54385 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200825113619.htm

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