title: Seasonal environmental changes regulate the expression of the histone variant macroH2A in an eurythermal fish.
abstract: Adaptation to cold and warm conditions requires dramatic change in gene expression. The acclimatization process of the common carp Cyprinus carpio L. in its natural habitat has been used to study how organisms respond to natural environmental changes. At the cellular level, adaptation to cold condition is accompanied by a dramatic alteration in nucleolar structure and a down regulation of the expression of ribosomal genes. We show that the enrichment of condensed chromatin in winter adapted cells is not correlated with an increase of the heterochromatin marker trimethyl and monomethyl K20H4. However, the expression of the tri methyl K4 H3 and of the variant histone macroH2A is significantly increased during the winter season together with a hypermethylation of CpG residues. Taking into account the properties of macroH2A toward chromatin structure and dynamics and its role in gene repression our data suggest that the increased expression of macroH2A and the hypermethylation of DNA which occurs upon winter-acclimatization plays a major role for the reorganization of chromatin structure and the regulation of gene expression during the physiological adaptation to a colder environment.
authors.affiliation: Millennium Institute for Fundamental and Applied Biology and Biological Sciences Department, Universidad Andres Bello, Santiago, Chile.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Pinto
authors.forename: Corinne
authors.initials: C
authors.lastname: Ivaldi
authors.forename: Mauricio
authors.initials: M
authors.lastname: Reyes
authors.forename: Cécile
authors.initials: C
authors.lastname: Doyen
authors.forename: Flore
authors.initials: F
authors.lastname: Mietton
authors.forename: Fabien
authors.initials: F
authors.lastname: Mongelard
authors.forename: Marco
authors.initials: M
authors.lastname: Alvarez
authors.forename: Alfredo
authors.initials: A
authors.lastname: Molina
authors.forename: Stefan
authors.initials: S
authors.lastname: Dimitrov
authors.forename: Manuel
authors.initials: M
authors.lastname: Krauskopf
authors.forename: Maria Ines
authors.initials: MI
authors.lastname: Vera
authors.forename: Philippe
authors.initials: P
authors.lastname: Bouvet
mesh_terms: D000064:Acclimatization; D000818:Animals; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D002347:Carps / Q000378:metabolism / Q000502:physiology*; D002467:Cell Nucleus / Q000737:chemistry / Q000648:ultrastructure; D019175:DNA Methylation; D004275:DNA, Ribosomal / Q000235:genetics / Q000378:metabolism; D006570:Heterochromatin / Q000378:metabolism; D006657:Histones / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000166:cytology; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D012621:Seasons
chemical_list: D015415:Biomarkers; D004275:DNA, Ribosomal; D006570:Heterochromatin; D006657:Histones; D012333:RNA, Messenger; C120756:macroH2A histone