A full suite of histone and histone modifying genes are transcribed in the dinoflagellate Lingulodinium

• Published in: PloS one Vol. 7; no. 4; p. e34340
• Main Authors: Roy, Sougata, Morse, David
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 04.04.2012; Public Library of Science (PLoS)
• Subjects: Aspergillus nidulans; Biology; Biomarkers - metabolism; Cell cycle; Cells, Cultured; Chlamydia; Chlamydia trachomatis; Chromatin; Cladistic analysis; Computational Biology; Conservation; Conserved sequence; Cyclin-dependent kinases; Deoxyribonucleic acid; Dinoflagellates; Dinoflagellida - genetics; Dinoflagellida - metabolism; DNA; DNA - genetics; DNA binding proteins; DNA methylation; DNA sequencing; Enzymes; Gene expression; Gene Expression Profiling; Gene sequencing; Genes; Histone-Lysine N-Methyltransferase - metabolism; Histones; Histones - genetics; Histones - metabolism; Immunoblotting; Kinases; Lingulodinium; Lingulodinium polyedrum; Microorganisms; Nucleosomes; Nucleosomes - genetics; Oligonucleotide Array Sequence Analysis; Pathogens; Phylogeny; Proteins; Protozoan Proteins - genetics; Protozoan Proteins - metabolism; Pyrrophycophyta; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA; RNA, Messenger - genetics; Tandem Mass Spectrometry; Transcription; Canada
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0034340

Dinoflagellates typically lack histones and nucleosomes are not observed in DNA spreads. However, recent studies have shown the presence of core histone mRNA sequences scattered among different dinoflagellate species. To date, the presence of all components required for manufacturing and modifying nucleosomes in a single dinoflagellate species has not been confirmed. Analysis of a Lingulodinium transcriptome obtained by Illumina sequencing of mRNA shows several different copies of each of the four core histones as well as a suite of histone modifying enzymes and histone chaperone proteins. Phylogenetic analysis shows one of each Lingulodinium histone copies belongs to the dinoflagellate clade while the second is more divergent and does not share a common ancestor. All histone mRNAs are in low abundance (roughly 25 times lower than higher plants) and transcript levels do not vary over the cell cycle. We also tested Lingulodinium extracts for histone proteins using immunoblotting and LC-MS/MS, but were unable to confirm histone expression at the protein level. We show that all core histone sequences are present in the Lingulodinium transcriptome. The conservation of these sequences, even though histone protein accumulation remains below currently detectable levels, strongly suggests dinoflagellates possess histones.