Contribution of Zranb3 to normal and stressed hematopoiesis

项目摘要 造血，骨髓中造血干细胞和祖细胞(HSPC)的过程 为造血系统产生所有成熟的血细胞，是生命所必需的。HSPC特别容易发生 DNA复制应激，因为它们在正常造血过程中的高复制率，当然在 应激诱导/紧急造血导致的突发性增殖。DNA复制压力不适当 被认为是导致基因组不稳定和细胞死亡，最终导致HSPC缺陷， 缺乏和/或骨髓衰竭。然而，在HSPC中缓解这种压力的蛋白质在很大程度上仍然存在 没有特征的。了解HSPC中响应DNA复制压力的蛋白质对于 了解如何在整个生命周期内保护HSPC的发展和运作。最近，Smarcal1和 ZRANB3是两种具有相同生化活性的翻叉和重塑蛋白。 人类癌细胞应对DNA复制压力和防止DNA复制叉崩塌，但它们的作用 在体内和在造血细胞中仍未被发现。Eischen实验室发现，虽然Smarcal1不是 它是正常造血所必需的，在应激/紧急造血过程中对HSPC是必不可少的。 目前，关于ZRANB3在体内的作用以及Smarcal1和ZRANB3的功能是否 体内造血细胞中的冗余。我们的初步数据表明，ZRANB3可能是HSPC和 在体内，它的功能与Smarcal1是非冗余的。因此，我们假设ZRANB3是一个基本的 HSPC中DNA复制应激反应的组成部分，并对其增殖起重要作用 和生存。为了验证这一假设，我们将使用小鼠模型以及小鼠和人类的主要模型 造血细胞。在目标1中，我们建议研究ZRANB3对正常造血的需求 以及所涉及的机制。在目标2中，我们将研究ZRANB3在DNA复制应激中的作用- 在应激/紧急造血过程中诱导的。拟议中的实验结果将显著 增加对正常情况下保护造血细胞的DNA复制应激反应的理解 并强调造血功能，防止造血细胞衰竭。 托马斯·杰斐逊大学的医学博士项目提供具有挑战性的全面培训， 将使我能够实现这项申请的目标，并成为一名成功的独立内科医生兼科学家。我的 培训将包括通过多种途径发展许多技能和增加知识。 得到了我的导师、论文委员会和其他科学家的支持。教育和职业发展 这份提案中概述的目标将帮助我实现成为一名成功的、独立的医生的目标- 科学家专注于血液学。

Project Summary Hematopoiesis, the process by which hematopoietic stem and progenitor cells (HSPCs) in the bone marrow produce all mature blood cells for the hematopoietic system, is required for life. HSPCs are particularly prone to DNA replication stress due to their high rates of replication during normal hematopoiesis and certainly during bursts of proliferation from stress-induced/emergency hematopoiesis. DNA replication stress that is not properly resolved is postulated to contribute to genomic instability and cell death, ultimately leading to HSPC defects, deficiencies and/or bone marrow failure. Yet, the proteins that mitigate such stress in HSPCs remain largely uncharacterized. Understanding the proteins that respond to DNA replication stress in HSPCs is essential to understanding how HSPC development and function is protected throughout a lifetime. Recently, Smarcal1 and Zranb3, two proteins with the same biochemical activity of fork reversal and remodeling, were determined in human cancer cells to respond to DNA replication stress and prevent DNA replication fork collapse, but their role in vivo and in hematopoietic cells remained unexplored. The Eischen lab discovered that while Smarcal1 is not required for normal hematopoiesis, it is essential for HSPCs during stressed/emergency hematopoiesis. Currently, little is known about Zranb3 in vivo, as well as whether the functions of Smarcal1 and Zranb3 are redundant in vivo in hematopoietic cells. Our preliminary data suggest Zranb3 may be essential for HSPCs and its functions are non-redundant with Smarcal1 in vivo. Therefore, we hypothesize Zranb3 is an essential component of the DNA replication stress response in HSPCs and significantly contributes to their proliferation and survival. To test this hypothesis, we will use mouse models and both mouse and human primary hematopoietic cells. In Aim 1, we propose to investigate the requirements of Zranb3 to normal hematopoiesis and the mechanism involved. In Aim 2, we will investigate the contribution of Zranb3 to DNA replication stress- induced during stressed/emergency hematopoiesis. Results from the proposed experiments will significantly increase understanding of the DNA replication stress response that protects hematopoietic cells during normal and stressed hematopoiesis and prevents hematopoietic cell failure. The MD/PhD program at Thomas Jefferson University provides challenging, comprehensive training that will allow me to fulfill the goals of this application and become a successful independent physician-scientist. My training will include the development of many skills and an increase of knowledge through multiple approaches supported by my mentor, thesis committee, and other scientists. The educational and career development objectives outlined in this proposal will help me fulfill my goal of becoming a successful, independent physician- scientist focused on hematology.