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Abstract
Reporting in Developmental Cell, Shea et al. (2015) show, using an inbred mouse strain, that "epivariation"-stochastic individual differences in DNA methylation-is a much greater contributor to the sperm methylome than is diet. They conclude that DNA methylation is not the mechanism underlying the dietary reprogramming of offspring phenotype.
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Affiliation(s)
- Emma Whitelaw
- Department of Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne 3086 VIC, Australia.
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Shea JM, Serra RW, Carone BR, Shulha HP, Kucukural A, Ziller MJ, Vallaster MP, Gu H, Tapper AR, Gardner PD, Meissner A, Garber M, Rando OJ. Genetic and Epigenetic Variation, but Not Diet, Shape the Sperm Methylome. Dev Cell 2015; 35:750-8. [PMID: 26702833 PMCID: PMC4691283 DOI: 10.1016/j.devcel.2015.11.024] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/25/2015] [Accepted: 11/21/2015] [Indexed: 01/13/2023]
Abstract
Paternal diet can impact metabolic phenotypes in offspring, but mechanisms underlying such intergenerational information transfer remain obscure. Here, we interrogate cytosine methylation patterns in sperm obtained from mice consuming one of three diets, generating whole genome methylation maps for four pools of sperm samples and for 12 individual sperm samples, as well as 61 genome-scale methylation maps. We find that "epivariation," either stochastic or due to unknown demographic or environmental factors, was a far stronger contributor to the sperm methylome than was the diet consumed. Variation in cytosine methylation was particularly dramatic over tandem repeat families, including ribosomal DNA (rDNA) repeats, but rDNA methylation was strongly correlated with genetic variation in rDNA copy number and was not influenced by paternal diet. These results identify loci of genetic and epigenetic lability in the mammalian genome but argue against a direct role for sperm cytosine methylation in dietary reprogramming of offspring metabolism.
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Affiliation(s)
- Jeremy M Shea
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Ryan W Serra
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Benjamin R Carone
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Hennady P Shulha
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Bioinformatics Core, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Alper Kucukural
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Bioinformatics Core, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Michael J Ziller
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Markus P Vallaster
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Hongcang Gu
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Andrew R Tapper
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Paul D Gardner
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Alexander Meissner
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Manuel Garber
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Bioinformatics Core, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Oliver J Rando
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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Abstract
Chromium is ubiquitous in the environment as Cr(III) and Cr(VI) oxidation states, which interconvert under environmentally and biologically relevant conditions (although Cr(III) usually predominates). While Cr(VI) is an established human carcinogen and a major occupational and environmental hazard, Cr(III) has long been regarded as an essential human micronutrient, although recent literature has cast serious doubts on the validity of this postulate. Despite five decades of research, no functional Cr-containing enzymes or cofactors have been characterized conclusively, and several hypotheses on their possible structures have been refuted. Gastrointestinal absorption pathways for both Cr(III) and Cr(VI) are apparent and whole-blood speciation can involve Cr(VI) uptake and reduction by red blood cells, as well as Cr(III) binding to both proteins and low-molecular-mass ligands in the plasma. DNA-damaging effects of Cr(VI) and anti-diabetic activities of Cr(III) are likely to arise from common mechanistic pathways that involve reactive Cr(VI/V/IV) intermediates and kinetically inert Cr(III)-protein and Cr(III)-DNA adducts. Both Cr(III) and Cr(VI) are toxic to plants and microorganisms, particularly Cr(VI) due to its higher bioavailability and redox chemistry. Some bacteria reduce Cr(VI) to Cr(III) without the formation of toxic Cr(V) intermediates and these bacteria are being considered for use in the bioremediation of Cr(VI)-polluted environments.
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Affiliation(s)
- Peter A. Lay
- School of Chemistry, The University of Sydney Sydney NSW 2006 Australia
| | - Aviva Levina
- School of Chemistry, The University of Sydney Sydney NSW 2006 Australia
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