Restricting calorie intake seems to promote longer lives in a wide range of organisms, from microbes to mammals. Some determined youth-seekers are already adopting reduced-calorie diets in an attempt to extend their lifespans. But it’s not clear yet that these anti-aging effects apply to humans, and the mechanisms by which they work in other organisms are not fully understood.
In the March issue of GENETICS, David McCleary and Jasper Rine delve into the complex relationship between calorie restriction (CR), chronological aging, and the histone deacetylase Sir2. Some work suggests Sir2 lengthens lifespan in low-glucose conditions in yeast, while other work finds no such effect. The researchers made a clever observation that allowed them to resolve these conflicting results: almost all yeast are grown on 2% glucose, which they suggest is actually borderline CR, since natural yeast substrates contain substantially more glucose. They employed a broader range of glucose concentrations to more fully capture the range of effects of Sir2 and CR on aging in yeast.
McCleary and Rine found that the effect of SIR2 deletion depended on both glucose level—high or low—and the media type—rich, which is full of assorted nutrients and peptide fragments, or minimal, which contains a precise but simple combination of amino acids and nutrients. Deletion of SIR2 extended lifespan only in high-glucose minimal media. But in rich media, deletion of SIR2 had little effect in high glucose and decreased lifespan in low glucose. In search of a mechanism, the researchers considered the cellular function of Sir2: to deacetylate specific sites on histone tails, leading to heterochromatin formation and gene silencing at the affected locus. They found that Sir2-dependent silencing at one such site, the HML locus, was affected by the media—the silencing was destabilized by high glucose in rich media, but the opposite was true in minimal media.
These results suggest a role for Sir2 as a regulator of yeast aging, lengthening or shortening lifespan depending on the environment. It’s certainly conceivable that in lean times, a longer chronological lifespan would be handy, allowing for reproduction to be put off until conditions improve. But what benefit could there be for a single-celled organism to shave time off its life? It’s possible that the shortened lifespans seen in nutrient-rich environments simply result from faster metabolism, more activity, and more risk of cellular damage, causing aging. But another intriguing possibility is that group selection is at work—if a population of yeast consists of genetically close individuals, killing off some individuals would free up nutrients and space for the next, possibly even better-adapted, generation.
CITATION:
McCleary, D.; Rine, J. Nutritional Control of Chronological Aging and Heterochromatin in Saccharomyces cerevisiae.
GENETICS, 205(3), 1179-1193.
DOI: 10.1534/genetics.116.196485
http://www.genetics.org/content/205/3/1179
Nicole Haloupek is a freelance science writer and a recent graduate of UC Berkeley's molecular and cell biology PhD program.
View all posts by Nicole Haloupek »Read more in
-
Early Career Leadership Spotlight: Julio Molina Pineda
We’re taking time to get to know the members of the GSA’s Early Career Scientist Committees. Join us to learn more about our early career scientist advocates. Julio Molina Pineda Policy and Advocacy University of Arkansas Research Interest My research interests focus on using model organisms to genetically dissect complex traits related to human disease. My…
-
Early Career Leadership Spotlight: Peiwei Chen
We’re taking time to get to know the members of the GSA’s Early Career Scientist Committees. Join us to learn more about our early career scientist advocates. Peiwei Chen Accessibility Subcommittee California Institute of Technology Research Interest Far from a harmonious place, the genome is a battleground, where every bit of DNA fights for inheritance and…
-
#Dros23 GSA Poster Award winners
We are pleased to announce the GSA Poster Award winners from the 64th Annual Drosophila Research Conference! Undergraduate and graduate student members of the GSA were eligible for the awards, and a hard-working team of postdocs volunteered their time as judges. Congratulations to all! Undergraduate Students 1st Place: Sofia Karter Lopez, University of Toronto “Rab11 mediates E-cadherin recycling during…
-
Congratulations to the Fall 2022 DeLill Nasser Awardees!
GSA is pleased to announce the recipients of the DeLill Nasser Award for Professional Development in Genetics for Fall 2022! Given twice a year to graduate students and postdoctoral researchers, DeLill Nasser Awards support attendance at meetings and laboratory courses. The award is named in honor of DeLill Nasser, a long-time GSA supporter and National Science Foundation…
-
New editors join GENETICS, G3 editorial boards
Several new editors are joining the GSA Journals. We’re excited to welcome Ricardo Zayas to the GENETICS editorial board under the Molecular Genetics of Development section, and on the G3: Genes|Genomes|Genetics board, we welcome Polly Campbell, Kevin Vogel, Joe Parker, and Ricardo Mallarino. Ricardo Zayas Associate Editor Ricardo Zayas is a Professor of Biology at…
-
Worms and Flies Provide Key Clues to Medical Mystery
This article is part of a series of posts outlining the history and impact of research in experimental organisms. The series is developed in collaboration with the GSA Public Communications and Engagement Committee. By the time Bertrand Might was six months old, it was clear something was amiss. His muscles weren’t developing normally; he was…
-
Congratulations to the 2023 Early Career Leadership Program Cohort!
The Genetics Society of America (GSA) is excited to announce the latest cohort of student, postdoc, and early-career research leaders joining the Early Career Leadership Program. Participants receive training and mentoring while serving on committees charged with understanding the needs, interests, concerns, and challenges of early career scientist members of the GSA. As part of…
-
GSA LOCI: Local Outreach Community Initiatives @ GSA Conferences
Highlights: Local Outreach Community Initiatives (LOCI): The Genetics Society of America is committed to supporting the communities of the host cities of our conferences. This new year, we are excited to reconnect with our GSA community in meaningful ways within and beyond our existing programming. The GSA membership has created a caring and supportive environment…
-
New members of the GSA Board of Directors: 2023–2025
We are pleased to announce the election of five new leaders to the GSA Board of Directors: 2023 Vice President/2024 President Mariana Wolfner Distinguished Professor of Molecular Biology and Genetics and Stephen H. Weiss Presidential Fellow My research has focused on the genes and pathways that mediate sexual development and reproduction, primarily in Drosophila. From…
-
Lance David Miller: Lighting Your Own Fire by Finding the Right Resources
By Daniel J. Gironda In the Paths to Science Policy series, we talk to individuals who have a passion for science policy and are active in advocacy through their various roles and careers. The series aims to inform and guide early career scientists interested in science policy. This series is brought to you by the…
-
Graça Almeida-Porada: The Importance of Communication in a Technologically Advancing World
By Daniel J. Gironda In the Paths to Science Policy series, we talk to individuals who have a passion for science policy and are active in advocacy through their various roles and careers. The series aims to inform and guide early career scientists interested in science policy. This series is brought to you by the…