title: Diversity and Divergence of Dinoflagellate Histone Proteins.
abstract: Histone proteins and the nucleosomal organization of chromatin are near-universal eukaroytic features, with the exception of dinoflagellates. Previous studies have suggested that histones do not play a major role in the packaging of dinoflagellate genomes, although several genomic and transcriptomic surveys have detected a full set of core histone genes. Here, transcriptomic and genomic sequence data from multiple dinoflagellate lineages are analyzed, and the diversity of histone proteins and their variants characterized, with particular focus on their potential post-translational modifications and the conservation of the histone code. In addition, the set of putative epigenetic mark readers and writers, chromatin remodelers and histone chaperones are examined. Dinoflagellates clearly express the most derived set of histones among all autonomous eukaryote nuclei, consistent with a combination of relaxation of sequence constraints imposed by the histone code and the presence of numerous specialized histone variants. The histone code itself appears to have diverged significantly in some of its components, yet others are conserved, implying conservation of the associated biochemical processes. Specifically, and with major implications for the function of histones in dinoflagellates, the results presented here strongly suggest that transcription through nucleosomal arrays happens in dinoflagellates. Finally, the plausible roles of histones in dinoflagellate nuclei are discussed.
authors.affiliation: Department of Biology, Indiana University, Bloomington, Indiana 47405 gkm359@gmail.com.
authors.forename: Georgi K
authors.identifier: http://orcid.org/0000-0003-1822-7273
authors.initials: GK
authors.lastname: Marinov
authors.affiliation: Department of Biology, Indiana University, Bloomington, Indiana 47405.
authors.forename: Michael
authors.initials: M
authors.lastname: Lynch
mesh_terms: D000595:Amino Acid Sequence; D005075:Biological Evolution; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D016000:Cluster Analysis; D004141:Dinoflagellida / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D014644:Genetic Variation; D016678:Genome; D023281:Genomics / Q000379:methods; D006657:Histones / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D019655:Quantitative Trait, Heritable; D012323:RNA Processing, Post-Transcriptional; D016415:Sequence Alignment; D014158:Transcription, Genetic
chemical_list: D002843:Chromatin; D006657:Histones
keywords: chromatin; dinoflagellates; histone code; histones; transcription 