GATA Factor Mechanisms in Erythroid Regeneration

摘要 红细胞生成，即生产红细胞(RBC)，是微调的，以满足生理需求。在.期间 再生或“应激性红细胞生成”由贫血引起，基因和蛋白质的子集在 与红细胞生成率的增加有关。对红系再生认识上的一个关键差距 关键在于红系祖细胞中基因调控网络的激活(由转录驱动 因素)是特定于压力的，或者在其他情况下代表更广泛的控制机制。此外，潜在的 在慢性贫血中，红系系统失去再生能力的病因通常还不清楚。我们 发现不育的Alpha基序结构域14(Samd14)基因在急性/慢性贫血模型中升高。 Samd14由转录因子GATA2调控，GATA2协调关键基因网络 在造血和血液病中的作用。GATA2占据的Samd14顺式元件(Samd14-Enh) 是在溶血性贫血模型中生存所必需的，但对于稳定状态的红细胞生成是必不可少的。红系 缺乏Samd14-Enh的前体细胞损害了c-Kit信号，这是一种典型的调控途径 造血和红细胞生成。这些结果揭示了GATA2-Samd14-c-Kit调控的参与 红系再生中的轴心。而含有SAM结构域的蛋白参与了造血和细胞 信号转导，其中一些在贫血中上调，它们的作用机制还不清楚。我们的数据 提示具有模拟Samd14-Enh特性的额外的增强剂队列是贫血调节的。我们 假设Samd14和额外的GATA2和再生激活(G2R)增强剂控制红系 再生。在目标1中，人类和小鼠的机械分析将定义对细胞的Samd14要求 红系祖细胞的信号与存活。AIM 2将描述GATA2和贫血调节(G2R)基因 管理围绕贫血反应的复杂生物学部门的网络。使用主服务器的方法 人类/小鼠细胞和创新的小鼠遗传模型方法将测试SAMD14机制(和其他 SAM结构域蛋白)在c-Kit信号转导和红系再生中的作用。这些目标将形成有价值的对比 动态平衡和再生红细胞生成机制、增强子基因敲除和基因敲除之间的关系 表型，以及包含相似序列和分子的功能不同的顺式元件之间 属性。通过阐明急性贫血中的GATA2-Samd14-c-Kit轴，以及全球/位点特异性的GATA2 Samd14-Enh类顺式元件的作用机制，我们期望这些研究将揭示基本的基因调控 红系再生的机制与包括贫血在内的血液病的关系。

ABSTRACT Erythropoiesis, the production of red blood cells (RBCs), is fine-tuned to meet physiological demands. During regeneration or “stress erythropoiesis” caused by anemia, a subset of genes and proteins are upregulated in association with an increased rate of RBC production. A critical gap in understanding erythroid regeneration hinges on whether the activation of gene regulatory networks in erythroid progenitors (driven by transcription factors) are stress-specific or represent broader control mechanisms in other contexts. Moreover, the underlying etiologies in which the erythroid system loses its ability to regenerate in chronic anemias are often unclear. We discovered that the Sterile Alpha Motif Domain-14 (Samd14) gene is elevated in models of acute/chronic anemia. Samd14 is regulated by the transcription factor GATA2, which coordinates a network of genes with critical functions in hematopoiesis and hematologic disease. The GATA2-occupied Samd14 cis-element (Samd14-Enh) is required for survival in a model of hemolytic anemia, but dispensable for steady state erythropoiesis. Erythroid progenitors lacking Samd14-Enh have impaired c-Kit signaling, a quintessential pathway regulating hematopoiesis and erythropoiesis. These results reveal the involvement of a GATA2-Samd14-c-Kit regulatory axis in erythroid regeneration. Whereas SAM domain-containing proteins are involved in hematopoiesis and cell signaling, and several are upregulated in anemia, their mechanisms of action are not well understood. Our data suggests additional cohorts of enhancers with properties mimicking the Samd14-Enh are anemia-regulated. We hypothesize that Samd14 and additional GATA2 and Regeneration-Activated (G2R) enhancers control erythroid regeneration. In Aim 1, mechanistic analyses in human and mouse will define Samd14 requirements for cell signaling and survival of erythroid progenitors. Aim 2 will delineate a GATA2 and anemia-regulated (G2R) gene network governing a sector of the complex biology surrounding anemia responses. Approaches using primary human/mouse cells and innovative mouse genetic model approaches will test SAMD14 mechanisms (and other SAM domain proteins) in c-Kit signaling and erythroid regeneration. These aims will establish valuable contrasts between homeostatic and regenerative erythropoietic mechanisms, enhancer knockout and gene knockout phenotypes, and between functionally-distinct cis-elements which contain similar sequence and molecular properties. By elucidating a GATA2-Samd14-c-Kit axis in acute anemia, and global/locus-specific GATA2 mechanisms of Samd14-Enh-like cis-elements, we expect these studies will reveal fundamental gene regulatory mechanisms in erythroid regeneration with implications in hematologic disease, including anemias.