Flies can pass the effects of stress to their young in the form of chromosomal modifications

Nov 11, 2011
Figure 1: When wm4 flies are exposed to heat stress, they display increased white expression, resulting in red eye pigmentation (right column). Offspring of these flies retain this effect (green line); if these 2nd generation flies are also heat-stressed (yellow line), the effects are still visible in their 5th generation offspring. © 2011 Ki-Hyeon Seong

Most people don’t realize the extent of the biochemical and physiological changes that stress causes; indeed, new research suggests that offspring might even be vulnerable to changes in gene expression wrought by chronic parental stress.

Different external traumas all appear to trigger a common response pathway, which is mediated in part by the activation transcription factor-2 (ATF-2) protein. “Environmental stress, psychological stresses, infection stress and nutrition stress can all activate ATF-2,” explains Shunsuke Ishii, a scientist at the RIKEN Advanced Science Institute in Tsukuba, whose group first cloned ATF-2 nearly two decades ago.

Ishii was inspired by studies in yeast suggesting that ATF-2 triggers chemical changes to chromatin, the material formed when chromosomal DNA wraps around histone proteins. These changes can markedly affect gene expression, a mechanism known as ‘epigenetic regulation’. In their recently published study, Ishii and his colleagues examined whether or not ATF-2 is associated with epigenetic regulation in the fruit fly Drosophila melanogaster.

The strain of D. melonogaster known as wm4 features a genomic rearrangement that results in epigenetic silencing of the white gene, a locus that controls eye color; and the researchers used this strain as their primary experimental model. They determined that ATF-2 normally binds to the chromatin and contributes to white silencing in these . However, when the flies were exposed to stress from heat or a high-salt diet, ATF-2 was released from the chromatin, which subsequently underwent chemical modifications that led to increased white expression.

Since epigenetic changes can be transmitted across generations, Ishii and colleagues performed a series of experiments in which heat-stressed flies were crossed with unstressed counterparts. Remarkably, offspring from these crosses maintained the increased white expression seen in the stressed parent. When these offspring were in turn subjected to heat stress and then crossed with unstressed flies, the effects were transmitted as far as the fifth generation (Fig. 1). “This shows that the effects of stress can be inherited without DNA sequence change,” says Ishii.

All of these effects were dependent on ATF-2. The researchers also identified dozens of genes whose activity may be potentially modulated by this factor during response. Ishii hopes to further explore the biological significance of this finding in future studies. “We are planning to identify such target of ATF-2 and prove the inheritance of their stress-induced expression change,” he says. “This could be correlated with various diseases.”

Explore further: Big-data analysis reveals gene sharing in mice

More information: Seong, K.-H., Dong, L., Shimizu, H., Nakamura, R. & Ishii, S. Inheritance of stress-induced, ATF-2-dependent epigenetic change. Cell 145, 1049–1061 (2011). www.cell.com/abstract/S0092-8674%2811%2900590-3

add to favorites email to friend print save as pdf

Related Stories

Silence of the genes

Jul 22, 2011

A molecular mechanism by which gene silencing is regulated at the genome-wide level in plants has been uncovered by a research team led by Motoaki Seki of the RIKEN Plant Science Center, Yokohama, Japan. ...

Does the impact of psychological trauma cross generations?

Sep 08, 2010

In groups with high rates of posttraumatic stress disorder (PTSD), such as the survivors of the Nazi Death Camps, the adjustment problems of their children, the so-called "Second Generation", have received attention by researchers. ...

Recommended for you

Big-data analysis reveals gene sharing in mice

23 hours ago

Rice University scientists have detected at least three instances of cross-species mating that likely influenced the evolutionary paths of "old world" mice, two in recent times and one in the distant past.

User comments : 4

Adjust slider to filter visible comments by rank

Display comments: newest first

maunas
2 / 5 (3) Nov 12, 2011
Yes, yes, it happens in humans also.I have long observed it to be so.
Cynical1
1 / 5 (2) Nov 12, 2011
It happens in all creatures. If the "stress" continues for enough generations (meaning that it is a permanant change), the info is encoded in DNA.
Pretty much describes the main mechanics of evolution.
DavidMcC
1 / 5 (1) Nov 12, 2011
A potential misunderstanding here is due to the use of the word "stress" instead of "eustress". Some readers may confuse "stress" with "distress", as happened in another recent thread on the effect of predatroy fish on gragonflies.
hush1
1 / 5 (1) Nov 12, 2011
What influences the capture or release of histone proteins?
Does this capture or release have duration?
Where is this 'duration'? There was no DNA change. The authors conjecture the 'flipped switch'(capture or release) was 'recorded' and genetically passed on - without DNA change.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.