title: Protein and DNA modifications: evolutionary imprints of bacterial biochemical diversification and geochemistry on the provenance of eukaryotic epigenetics.
abstract: Epigenetic information, which plays a major role in eukaryotic biology, is transmitted by covalent modifications of nuclear proteins (e.g., histones) and DNA, along with poorly understood processes involving cytoplasmic/secreted proteins and RNAs. The origin of eukaryotes was accompanied by emergence of a highly developed biochemical apparatus for encoding, resetting, and reading covalent epigenetic marks in proteins such as histones and tubulins. The provenance of this apparatus remained unclear until recently. Developments in comparative genomics show that key components of eukaryotic epigenetics emerged as part of the extensive biochemical innovation of secondary metabolism and intergenomic/interorganismal conflict systems in prokaryotes, particularly bacteria. These supplied not only enzymatic components for encoding and removing epigenetic modifications, but also readers of some of these marks. Diversification of these prokaryotic systems and subsequently eukaryotic epigenetics appear to have been considerably influenced by the great oxygenation event in the Earth's history.
authors.affiliation: National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894.
authors.forename: L
authors.initials: L
authors.lastname: Aravind
authors.affiliation: National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894.
authors.forename: A Maxwell
authors.initials: AM
authors.lastname: Burroughs
authors.affiliation: National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894.
authors.forename: Dapeng
authors.initials: D
authors.lastname: Zhang
authors.affiliation: National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894.
authors.forename: Lakshminarayan M
authors.initials: LM
authors.lastname: Iyer
mesh_terms: D044822:Biodiversity; D019175:DNA Methylation; D004269:DNA, Bacterial / Q000737:chemistry* / Q000378:metabolism; D057890:Epigenomics; D056890:Eukaryota / Q000235:genetics*; D019143:Evolution, Molecular; D006657:Histones / Q000378:metabolism; D008958:Models, Molecular; D010766:Phosphorylation; D010802:Phylogeny; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D054875:Ubiquitination
chemical_list: D004269:DNA, Bacterial; D006657:Histones; D011506:Proteins