title: Histone epigenetic marks in heterochromatin and euchromatin of the Chagas' disease vector, Triatoma infestans.
abstract: Triatoma infestans, a vector of Chagas' disease, shows several particular cell biology characteristics, including the presence of conspicuous heterochromatic bodies (chromocenters) where DNA methylation has not been previously detected. Whether histone modifications contribute to the condensed state of these bodies has not yet been studied. Here, we investigated epigenetic modifications of histones H3 and H4 and presence of the non-histone heterochromatin protein (HP1-α) in the chromocenters and euchromatin of T. infestans cell nuclei, using immunocytochemistry. The effect of different concentrations of the histone deacetylase inhibitors valproic acid (VPA) and sodium butyrate (NaBt) on chromocenter condensation was visually examined; in VPA-treated specimens, this effect was also analyzed by image analysis. Trimethylated H3K9 signals, which were revealed in chromocenter and non-chromocenter areas, were strongest in chromocenters, whereas selected acetylated histone marks and mono- and dimethylated H3K9 and H4K20 signals were detected only in euchromatin. Weak trimethylated H4K20 signals and variable distribution of HP1-α were detected in chromocenters of part of the cellular population analyzed. Although specific VPA and NaBt treatment conditions affected the heterochromatin condensation pattern, they did not induce a decrease in survival and molting rates of the T. infestans nymphs. The VPA-induced chromatin remodeling was not accompanied by induction of H3K9 acetylation in chromocenters. Present findings regarding histone modifications and effects following VPA or NaBt treatments did not yet solve the question of which factors are responsible for maintenance of the condensed state of chromocenters in T. infestans. A possibility requiring further investigation remains on histone methylation marks and/or non-histone proteins.
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, University of Campinas (Unicamp), 13083-862 Campinas, SP, Brazil.
authors.forename: Elenice M
authors.initials: EM
authors.lastname: Alvarenga
authors.affiliation: Superintendence for Control of Endemic Diseases (SUCEN), 13840-000 Mogi-Guaçu, SP, Brazil.
authors.forename: Vera L C C
authors.initials: VL
authors.lastname: Rodrigues
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, University of Campinas (Unicamp), 13083-862 Campinas, SP, Brazil; Department of Morphology, Institute of Biomedical Sciences, Federal University of Uberlândia, 38405-320 Uberlândia, MG, Brazil.
authors.forename: Alberto S
authors.initials: AS
authors.lastname: Moraes
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, University of Campinas (Unicamp), 13083-862 Campinas, SP, Brazil.
authors.forename: Luisa S
authors.initials: LS
authors.lastname: Naves
authors.affiliation: Department of Genetics, "Luiz de Queiroz" College of Agriculture (ESALQ), University of São Paulo (USP), 13418-900 Piracicaba, SP, Brazil.
authors.forename: Mateus
authors.initials: M
authors.lastname: Mondin
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, University of Campinas (Unicamp), 13083-862 Campinas, SP, Brazil.
authors.forename: Marina B
authors.initials: MB
authors.lastname: Felisbino
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, University of Campinas (Unicamp), 13083-862 Campinas, SP, Brazil. Electronic address: mlsmello@unicamp.br.
authors.forename: Maria Luiza S
authors.initials: ML
authors.lastname: Mello
mesh_terms: D000818:Animals; D014355:Chagas Disease; D042002:Chromatin Assembly and Disassembly; D059006:Chromosomes, Insect / Q000235:genetics / Q000378:metabolism; D004199:Disease Vectors; D044127:Epigenesis, Genetic; D022041:Euchromatin / Q000235:genetics / Q000378:metabolism*; D006570:Heterochromatin / Q000235:genetics / Q000378:metabolism*; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006657:Histones / Q000378:metabolism*; D019476:Insect Proteins / Q000378:metabolism*; D008297:Male; D014224:Triatoma / Q000166:cytology / Q000235:genetics*; D014635:Valproic Acid / Q000494:pharmacology
chemical_list: D022041:Euchromatin; D006570:Heterochromatin; D056572:Histone Deacetylase Inhibitors; D006657:Histones; D019476:Insect Proteins; D014635:Valproic Acid
keywords: Epigenetics; Heterochromatin; Histone deacetylase inhibitors; Image analysis; Immunocytochemistry; Triatoma infestans