Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas, Suipacha 351, 2000, Rosario, Argentina.
Int J Parasitol. 2009 May;39(6):665-73. doi: 10.1016/j.ijpara.2008.11.013. Epub 2008 Dec 24.
Histone tail post-translational modifications (acetylation, methylation, phosphorylation, ubiquitination and ADP-ribosylation) regulate many cellular processes. Among these modifications, phosphorylation, methylation and acetylation have already been described in trypanosomatid histones. Bromodomains, together with chromodomains and histone-binding SANT domains, were proposed to be responsible for "histone code" reading. The Trypanosoma cruzi genome encodes four coding sequences (CDSs) that contain a bromodomain, named TcBDF1-4. Here we show that one of those, TcBDF2, is expressed in discrete regions inside the nucleus of all the parasite life cycle stages and binds H4 and H2A purified histones from T. cruzi. Immunolocalization experiments using both anti-histone H4 acetylated peptides and anti-TcBDF2 antibodies determined that TcBDF2 co-localizes with histone H4 acetylated at lysines K10 and K14. TcDBF2 and K10 acetylated H4 interaction was confirmed by co-immunoprecipitation. It is also shown that TcBDF2 was accumulated after UV irradiation of T. cruzi epimastigotes. These results suggest that TcBDF2 could be taking part in a chromatin remodelling complex in T. cruzi.
组蛋白尾部翻译后修饰(乙酰化、甲基化、磷酸化、泛素化和 ADP-核糖基化)调节许多细胞过程。在这些修饰中,磷酸化、甲基化和乙酰化已在原生动物组蛋白中得到描述。溴结构域,与染色质结构域和组蛋白结合 SANT 结构域一起,被认为负责“组蛋白密码”读取。克氏锥虫基因组编码四个编码序列(CDS),包含一个溴结构域,称为 TcBDF1-4。在这里,我们表明其中一个,TcBDF2,在寄生虫所有生命周期阶段的核内离散区域表达,并结合 H4 和 H2A 从 T. cruzi 纯化的组蛋白。使用抗组蛋白 H4 乙酰化肽和抗 TcBDF2 抗体的免疫定位实验确定 TcBDF2 与赖氨酸 K10 和 K14 乙酰化的组蛋白 H4 共定位。TcDBF2 和 K10 乙酰化 H4 的相互作用通过共免疫沉淀得到证实。还表明,在 UV 照射克氏锥虫前鞭毛体后,TcBDF2 积累。这些结果表明,TcBDF2 可能参与了克氏锥虫的染色质重塑复合物。