Chromatin remodeling activity of C-module-binding factor from Dictyostelium discoideum

动态组蛋白甲基化在转录调控、基因组稳定性和表观遗传中起着重要作用。在过去的十年里，许多文献已经证实，组蛋白去甲基酶可以逆转组蛋白H3和H4氨基末端不同赖氨酸和精氨酸残基的甲基化。这些酶大多具有Jumonji(JmjC)结构域，能够通过氧化去甲基化反应去除组蛋白中的甲基。网柄类是一种古老的单细胞生物，有一个兼性的多细胞阶段，在这个阶段细胞分化成几种细胞类型，并协作建立子实体。人们对盘基鞭毛虫模型中的基因表达进行了详细的研究，但我们对染色质重塑在该生物中对基因调控的贡献知之甚少。Discoideum的基因组编码13个JmjC蛋白，这些蛋白被认为是组蛋白去甲基酶。我们将在基于Dictyostelials的表达系统中表达这些JmjC蛋白，并使用合成组蛋白多肽进行体外去甲基化实验来研究它们的催化活性。此外，我们将扩展我们之前关于JmjC家族转录调控因子CBFA的工作，并研究CBFA在盘状芽孢杆菌基因组中激活或抑制其靶基因表达的多蛋白复合体CBFA。

Dynamic histone methylation plays an important role in the regulation of transcription, genome stability and epigenetic inheritance. It has been established in a multitude of publications over the last ten years that methylations of distinct lysine and arginine residues in the amino-terminal tails of histones H3 and H4 can be reversed by histone demethylases. Most of these enzymes possess Jumonji (JmjC) domains that are capable of removing methyl groups from histones by an oxidative demethylation reaction. Dictyostelids are ancient unicellular organisms that have a facultative multicellular phase in which the cells differentiate into several cell types and collaborate to build up fruiting bodies. Gene expression in the model dictyostelid, Dictyostelium discoideum, has been studied in much detail, but our knowledge on the contribution of chromatin remodeling to gene regulation in this organism is scarce. The genome of D. discoideum encodes 13 JmjC proteins that come into consideration as putative histone demethylases. We will express these JmjC proteins in a Dictyostelium-based expression system and investigate their catalytic activities based on in vitro demethylation assays using synthetic histone peptides. In addition, we will expand our previous work on the JmjC family transcription regulator CbfA and investigate in which multiprotein complexes CbfA acts to either activate or suppress the expression of its target genes in the D. discoideum genome.