title: Post-translational modifications of Trypanosoma cruzi histone H4.
abstract: Histone tails provide sites for a variety of post-translational modifications implicated in the control of gene expression and chromatin assembly. As both histones and control of gene expression in trypanosomes are highly divergent compared to most eukaryotes, post-translational modifications of Trypanosoma cruzi histones were investigated. After in vivo incubation of live parasites with radiolabeled precursors, histone H4 mainly incorporates [(3)H]-acetyl, and to a lesser extent [(3)H]-methyl residues. In contrast, histone H3 preferentially incorporates [(3)H]-methyl residues. The modifications of histone H4 were further characterized by mass spectrometry. MALDI-TOF-TOF-MS analysis revealed that peptides from histone H4 amino-terminus, obtained by either endoproteinase Glu-C or endoproteinase Arg-C digestion, contain isoforms with 14 and 42Da additions, suggesting the presence of simultaneous acetylations and/or methylations. Tandem mass spectrometry analysis demonstrated that the N-terminal alanine is methylated, and lysine residues at positions 4, 10, 14 and 57 are acetylated; lysine at position 18 is mono-methylated, while arginine at position 53 is dimethylated. Immunoblotting analyses using specific antibodies raised against synthetic and acetylated peptides of T. cruzi histone H4 indicate that lysine 4 is acetylated in the majority of histone H4, while other acetylations at the N-terminus portion of histone H4 are less abundant.
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, R. Botucatu 862 8(a), 04023-062 São Paulo, Brazil.
authors.forename: Julia Pinheiro Chagas
authors.initials: JP
authors.lastname: da Cunha
authors.forename: Ernesto Satoshi
authors.initials: ES
authors.lastname: Nakayasu
authors.forename: Igor Correia
authors.initials: IC
authors.lastname: de Almeida
authors.forename: Sergio
authors.initials: S
authors.lastname: Schenkman
mesh_terms: D000107:Acetylation; D000595:Amino Acid Sequence; D000818:Animals; D006657:Histones / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification; D008745:Methylation; D008969:Molecular Sequence Data; D010455:Peptides; D011499:Protein Processing, Post-Translational; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053719:Tandem Mass Spectrometry; D014349:Trypanosoma cruzi / Q000737:chemistry / Q000235:genetics*
chemical_list: D006657:Histones; D010455:Peptides; D015800:Protozoan Proteins