HP1γ associates with euchromatin and heterochromatin in mammalian nuclei and chromosomes

摘要: Heterochromatin protein 1 (HP1) is a nonhistone chromosomal protein, first identified in Drosophila, that plays dose-dependent role gene silencing. Three orthologs, HP1alpha, HP1beta, and HP1gamma, have been characterized mammals. While HP1alpha HP1beta unambiguously localized heterochromatin by immunocytochemical methods, HP1gamma has found either exclusively associated with euchromatin or present both heterochromatin. Here, using an antibody directed against peptide epitope at the carboxyl-terminal end of molecule, we localize compartments interphase nuclei, as well pericentromeric chromatin arms mitotic chromosomes 3T3 cells. This dual location was also observed nuclei expressing fusion green fluorescent protein. In contrast, when distribution analyzed antibodies amino-terminal epitope, detectable not heterochromatin, except for transient staining during late S phase, undergoes replication. These data suggest controversial immunolocalization due to use topologically distinct epitopes, those molecule being selectively masked nonreplicative