Hematopoietic Signaling Pathway Mechanism in a GATA Factor-Dependent Network

在人类GATA2基因座，两个不同的顺式元件(+9.5和-77)的突变会引发免疫缺陷、骨髓增生异常综合征和/或急性髓系白血病。为了确定必需的GATA-2靶基因，我们实施了基于序列和分子标准的多组学优先排序策略。其中，这一分析揭示了GATA-2对不育阿尔法基序(SAM)结构域14(Samd14)表达的调节。机制研究证实，Samd14(和GATA-2占据的Samd14增强子(Samd14-Enh))促进造血干/祖细胞(HSPC)功能，促进成人造血再生，是在严重贫血中生存所必需的。Samd14-Enh通过致癌的SCF/c-Kit途径促进细胞信号转导，促进生存。Samd14促进SCF/c-Kit信号转导和造血祖细胞功能的关键机制尚不清楚。贫血激活的GATA2和Samd14的转录依赖于增强子，为定义GATA-2和贫血激活的再生基因网络奠定了基础，涉及许多有趣的和尚未研究的网络成分。利用Cobre在UNMC的赞助设施以及与Cobre项目负责人的合作，这些目标将严格确定Samd14如何促进SCF/c-Kit信号(目标1)、包含新的SAM结构域基因的造血功能(目标2)以及Samd14在造血环境中的功能(目标3)。拟议的项目与内布拉斯加州分子靶标发现和开发中心的总体使命高度相关。我们将定义调控完整的致癌细胞信号通路(SCF/c-Kit)的全新分子机制，以确定治疗靶点。项目负责人的合作、Cobre CORE提供的资源以及科学/职业指导的支持相结合，将极大地增强科学发现的影响和竞争R01级资金的成功。

At the human GATA2 locus, disruption of two distinct cis-elements (+9.5 and -77) instigate immunodeficiency,myelodysplastic syndrome and/or acute myeloid leukemia. To define essential GATA-2 target genes, we implemented a multi-omics prioritization strategy based on sequence and molecular criteria. Among others, this analysis revealed GATA-2 regulation of Sterile Alpha Motif(SAM) Domain 14 (Samd14) expression. Mechanistic studies established that Samd14 (and the GATA-2-occupied Samd14 enhancer (Samd14-Enh)) promotes hematopoietic stem/progenitor cell (HSPC) function, facilitates regeneration in adult hematopoiesis, and is required for survival in severe anemia. Samd14-Enh promotes cell signaling through the oncogenic SCF/c-Kit pathway, conferring survival. The key mechanisms whereby Samd14 promotes SCF/c-Kit signaling and hematopoietic progenitor function are not understood. Anemia-activated Gata2 and Samd14 transcription is enhancer-dependent, establishing a foundation for defining a GATA-2 and anemia-activated gene network in regeneration, involving many intriguing and unstudied network constituents. Utilizing COBRE-sponsored facilities at UNMC and collaborations with COBRE program leaders, these aims will rigorously establish how Samd14 promotes SCF/c-Kit signaling (Aim 1), the hematopoietic function of a new SAM-domain containing gene (Aim 2), and the function of Samd14 in hematopoietic contexts (Aim 3). The proposed project is highly relevant to the overall mission of the “Nebraska Center for Molecular Target Discovery and Development”. We will define completely novel molecular mechanisms regulating an integral, oncogenic cell signaling pathway (SCF/c-Kit) with the goal of identifying therapeutic targets. The combination of Project Leader collaborations, resources provided by COBRE Cores, and the support of scientific/career mentorship will greatly enhance the impact of scientific discoveries and success of competing for R01-level funding.