Post-translational modifications of Trypanosoma cruzi histone H4

• Published in: Molecular and biochemical parasitology 2006-12, Vol.150 (2), p.268-277
• Main Authors: da Cunha, Julia Pinheiro Chagas, Nakayasu, Ernesto Satoshi, de Almeida, Igor Correia, Schenkman, Sergio
• Format: Article
• Language: English
• Subjects: acetonitrile; Acetylation; ACN; Amino Acid Sequence; Animals; Chromatin; electrospray ionization ion-trap mass spectrometry; electrospray ionization quadrupole time-of-flight mass spectrometry; ESI-IT-MS; ESI-QTOF-MS; Histone H4; Histones - chemistry; Histones - genetics; Histones - isolation & purification; MALDI-TOF-MS; Mass spectrometry; matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; Methylation; Molecular Sequence Data; Nac; non-acetylated; PBS; Peptides; phosphate-buffered saline; post-translational modification; Protein Processing, Post-Translational; Protozoan Proteins - chemistry; Protozoan Proteins - genetics; Protozoan Proteins - isolation & purification; PTM; Spectrometry, Mass, Electrospray Ionization; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Tandem Mass Spectrometry; TAU-PAGE; TFA; trifluoroacetic acid; triton-acetic acid-urea-polyacrylamide gel electrophoresis; Trypanosoma cruzi; Trypanosoma cruzi - chemistry; Trypanosoma cruzi - genetics
• ISSN: 0166-6851; 1872-9428
• DOI: 10.1016/j.molbiopara.2006.08.012

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 [3H]-acetyl, and to a lesser extent [3H]-methyl residues. In contrast, histone H3 preferentially incorporates [3H]-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.