The Role of Mi2/NuRD Complex on the Expression of Human Gamma-Globin Gene

描述(申请人提供)：Mbd2被认为通过招募Mi2/NuRD抑制物复合体而在某些基因的沉默中发挥作用。为了更好地研究MI2/NuRD复合体如何在γ-珠蛋白沉默中发挥作用，我们已经着手在人类造血祖细胞中研究这一模型。当在分化介质中培养时，这些细胞模仿发育过程中发生的血红蛋白开关。由于在携带人类β基因的小鼠红系细胞上敲除Mi2的影响是敲除MBD2的几倍，因此将对Mi2进行研究，以确定其是否作用于MBD2-NuRd复合体之外。此外，MBD2在γ-珠蛋白基因表达中的作用也将在镰状细胞小鼠模型中进行研究。通过将Mbd2-/-小鼠与镰状细胞小鼠杂交，我们将确定切除Mbd2是否能够改善这种情况的影响。该项目对血红蛋白疾病(如镰状细胞性贫血和β地中海贫血)患者具有临床意义，在这些患者中，诱导γ-珠蛋白表达具有治疗效果。如果在体内模型中敲除MBD2会像之前在体外显示的那样，在γ-珠蛋白的表达上产生相当大的变化，这将使这种蛋白成为这些疾病的良好靶点。此外，通过表征甲基胞嘧啶蛋白结合复合体的组成和相互作用，我们可以潜在地识别其他可能的靶标。这种有针对性的方法可能会产生一种针对β-地中海贫血等疾病的更具组织特异性的治疗方法，为临床医生提供比目前治疗更好的选择。研究特定的蛋白质相互作用和基因表达的机制导致了非常成功的靶向治疗的发展(特别是格列卫治疗慢性粒细胞白血病)。这是我研究的目标，建立一个更好的理解过程，这将对未来的治疗产生重大影响。

DESCRIPTION (provided by applicant): MBD2 is thought to play a role in the silencing of certain genes by recruiting Mi2/NuRD repressor complex. To best study how the Mi2/NuRD complex plays a role in the silencing of γ-globin, we have set out to study this model in human hematopoietic progenitor cells. When cultured on a differentiation medium, these cells mimic the hemoglobin switch that occurs during development. Because knocking down Mi2 on mouse erythroid cells bearing the human β-locus had several fold greater effect than knocking down MBD2, Mi2 will be studied to determine if it acts outside of the MBD2-NuRD complex. Furthermore, the role of MBD2 in γ-globin gene expression will also be studied in the context of a sickle cell mouse model. By crossing MBD2-/- mice with sickle cell mice, we will determine whether ablation of MBD2 is able to ameliorate the effects of this condition. This project has clinical significance for patients with hemoglobinopathies (e.g., sickle cell anemia and beta thalassemia), where induction of γ-globin expression has a therapeutic effect. If knocking down MBD2 in an in vivo model produces a considerable change in the expression of γ-globin, as has been previously shown in vitro, this makes such protein a good target in these diseases. Moreover, by characterizing the components and interactions of the methylcytosine protein binding complex we could potentially identify other possible targets. This targeted approach may yield a more tissue-specific treatment to conditions such as β-thalasemia, providing clinicians with better options than current treatments. Studying specific protein interactions and mechanisms of gene expression has led to the development of highly successful targeted treatments (notably, Gleevec for Chronic Myelogenous Leukemia). This is the goal of my research, to build a better understanding of processes that will have a great impact on the future treatments.