Higgs Douglas R, Vernimmen Douglas, De Gobbi Marco, Anguita Eduardo, Hughes Jim, Buckle Veronica, Iborra Franciso, Garrick David, Wood William G
MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK.
Biochem Soc Symp. 2006(73):11-22. doi: 10.1042/bss0730011.
In the post-genomic era, a great deal of work has focused on understanding how DNA sequence is used to programme complex nuclear, cellular and tissue functions throughout differentiation and development. There are many approaches to these issues, but we have concentrated on understanding how a single mammalian gene cluster is activated or silenced as stem cells undergo lineage commitment, differentiation and maturation. In particular we have analysed the alpha globin cluster, which is expressed in a cell-type- and developmental stage-specific manner in the haemopoietic system. Our studies include analysis of the transcriptional programme that accompanies globin gene activation, focusing on the expression of relevant transcription factors and cofactors. Binding of these factors to the chromosomal domain containing the alpha globin cluster has been characterized by ChIP (chromatin immunoprecipitation). In addition, we have monitored the epigenetic modifications (e.g. nuclear position, timing of replication, chromatin modification, DNA methylation) that occur as the genes are activated (in erythroid cells) or silenced (e.g. in granulocytes) as haemopoiesis proceeds. Together, these observations provide a uniquely well-characterized model illustrating the mechanisms that regulate and memorize patterns of mammalian gene expression as stem cells undergo lineage specification, differentiation and terminal maturation.
在后基因组时代，大量工作聚焦于理解在整个分化和发育过程中，DNA序列是如何被用于编程复杂的细胞核、细胞和组织功能的。解决这些问题有多种方法，但我们专注于了解当干细胞经历谱系定向、分化和成熟时，单个哺乳动物基因簇是如何被激活或沉默的。特别是，我们分析了α珠蛋白基因簇，它在造血系统中以细胞类型和发育阶段特异性的方式表达。我们的研究包括对伴随珠蛋白基因激活的转录程序的分析，重点关注相关转录因子和辅助因子的表达。这些因子与包含α珠蛋白基因簇的染色体结构域的结合已通过染色质免疫沉淀（ChIP）进行了表征。此外，随着造血过程的进行，当基因在（红细胞中）被激活或（例如在粒细胞中）被沉默时，我们监测了发生的表观遗传修饰（如核位置、复制时间、染色质修饰、DNA甲基化）。这些观察结果共同提供了一个独特的、特征明确的模型，阐明了在干细胞经历谱系特化、分化和终末成熟时，调控和记忆哺乳动物基因表达模式的机制。
