New Study suggests that DNA reacts to the seasons

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Discussion Overview

The discussion centers around a study suggesting that DNA may react to seasonal changes, particularly in relation to gene expression and its implications for human immunity and physiology. Participants explore the nuances of how DNA and gene expression are affected by environmental factors, with a focus on inflammation, metabolism, and epigenetic modifications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants argue that while DNA itself does not change, the profile of gene expression varies with the seasons, which is a response to environmental conditions.
  • Others clarify that changes in gene expression are linked to chemical modifications, such as methylation, rather than alterations in the DNA sequence itself.
  • A participant suggests that the location of chemical tags on DNA may vary with the seasons, indicating a potential area for further research.
  • One participant introduces the concept of sirtuins, particularly sirt3, and its association with longevity and cold exposure, noting the ongoing debate about the role of sirtuins in aging.
  • Another participant discusses the role of O-GlcNAc modifications in metabolism and gene regulation, emphasizing its connection to seasonal metabolic changes and epigenetic processes.

Areas of Agreement / Disagreement

Participants express differing views on the implications of the study, particularly regarding the nature of DNA changes and the role of gene expression. There is no consensus on the broader implications of these findings for seasonal healthcare or the specifics of metabolic changes.

Contextual Notes

Limitations include the complexity of gene expression mechanisms, the dependence on specific definitions of DNA changes versus gene expression changes, and the unresolved nature of how seasonal factors influence metabolic processes.

jedishrfu
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http://www.wired.com/2015/05/dna-changes-seasons-just-like-weather/

AH, MY SWEET summer child. What do you know of inflammation? Inflammation is for the winter, when genes uncoil in your blood and messengers send codes containing the blueprints for proteins to protect you from the harsh diseases of the cold. Inflammation is for those long nights, when the sun hides its face, or rain clouds block the sky, and trillions of little T-cells are born to fight the diseases of cold and flu season.
 
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Typical news headline with an article full of misunderstanding. An individual's DNA doesn't change, it's the profile of gene expression that does. It doesn't seem surprising that gene expression of certain cells would change in response to different seasons (it's fairly obvious that our bodies react and adapt to different environmental conditions) but the study is interesting for gathering data on this phenomenon, particularly with regard to immunology. That last bit could have important implications for seasonal healthcare provision.

Original paper:

Widespread seasonal gene expression reveals annual differences in human immunity and physiology
Dopico et al (2015)
Nature Communications
http://www.nature.com/ncomms/2015/150512/ncomms8000/full/ncomms8000.html
 
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Yes, the paper does not examine the individuals' DNA at all, just the amount of mRNA produced from the DNA. These changes in could be caused by changes in the DNA, but these changes are not due to changes to the sequence of the DNA, but to certain chemical tags (methyl groups) that get added to the DNA. These chemical tags that get added to the DNA and to the histone proteins that package the DNA in the nucleus help determine which DNA sequences are available and able to be expressed, and which DNA sequences are unavailable to be expressed. It would be an interesting follow up study to see if location of these chemical tags change with the seasons as well.

I wonder what this suggests for research on these tissues. Will experiments done during the summer give different results than experiments done in the winter?
 
It's worth noting that there is some controversy surrounding whether the sirtuin genes are involved in aging and longevity (see these news articles from Science and Nature or this nice summary from the http://pipeline.corante.com/archives/2011/09/22/the_latest_sirtuin_controversy.php[/URL] blog).
 
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It has long been observed that metabolism changes with seasons. The O-glcnac modification directly descends from glucose metabolism and is involved in writing almost every aspect of your epigenetic code, many other important gene regulatory processes, and internal clocks:

O-glcnac is invovled in the histone code:
http://www.ncbi.nlm.nih.gov/pubmed/21045127

O-glcnac is inovled in regulating DNA methylation:
http://www.ncbi.nlm.nih.gov/pubmed/23729667

O-glcnac is also involved with the protein complex that regulates histone acetylation:
http://www.sciencedirect.com/science/article/pii/S0092867402008103
http://stke.sciencemag.org/content/2002/142/tw261.abstract

O-glcnac regulates the circadian rythm:
http://www.ncbi.nlm.nih.gov/pubmed/23395176

O-glcnac regulates RNA poly II transcription and a whole bunch of transcription factors have their activity regulated by sugar metabolism:
http://www.ncbi.nlm.nih.gov/pubmed/8486697
http://www.ncbi.nlm.nih.gov/pubmed/22605332
http://www.nature.com/nrc/journal/v11/n9/fig_tab/nrc3114_F1.html
Too many journal articles to read, but the main point is that many animals alter their metabolism during a period of hibernation. Even humans have documented changes in metabolism due to seasonal changes. Metabolism is essentially an extraordinary biosensor that links the environment, space, and time and digests that information to regulate the metabolic fluxes that produce the concentrations of UDP-GlcNAc--the metabolite responsible for the O-GlcNAc modification. If you were to permeabilize a cell to let in certain types of lectins (proteins that bind to sugar), you'd surprisingly find that chromatin for some reason is absolutely covered in sugar. We now recognize that almost every type of machinery involved in genetic transcription, epigenetic modifications, and even almost all of the proteins involved in higher order chromatin structure are in some way regulated by O-GlcNAc (which is why you find chromatin covered in sugar with lectins). O-GlcNAc is the link between environment/stress/and nutrition and epigenetics/genetic expression.