Oocyte polarity and BMP-mediated dorsoventral patterning

卵母细胞极性和 BMP 介导的背腹模式

• 批准号: 10626770
• 负责人: Mary C. Mullins
• 金额: $ 66.25万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10626770
• 关键词: Actins; Address; Adult; Amyloid; Amyloid Proteins; Animals; Anterior; Balbiani Body; Biological; Bone Morphogenetic Proteins; Bone Regeneration; Cardiovascular system; Cell Polarity; Cells; Cytoskeleton; Defect; Development; Disease; Dissociation; Dorsal; Embryo; Embryonic Development; Endodontics; Epithelium; Exhibits; Female; Fiber; Fishes; Gene Expression; Genes; Golgi Apparatus; Hallmark Cell; Health; Human; In Vitro; Insecta; Kidney Diseases; Limb structure; Mammals; Mediating; Medical; Membrane; Methods; Microtubules; Mitochondria; Neoplasm Metastasis; Neurodegenerative Disorders; Oocytes; Oogenesis; Organ; Orthopedics; Ovary; Pattern; Phase Transition; Phosphorylation; Proteins; Pulmonary Hypertension; RNA; Rana; Ribonucleoproteins; Role; Shapes; Signal Transduction; Signaling Protein; Specific qualifier value; Structure; Testing; Therapeutic; Time; Tissue Engineering; Tissues; Translating; Vertebrates; Zebrafish; body system; bone repair; cell fate specification; cell type; crosslink; egg; extracellular; genetic analysis; morphogens; mutant; protein aggregation; response; spatiotemporal; synucleinopathy; vertebrate embryos

Bone Morphogenetic Protein (BMP) signaling directs the development of multiple organs and tissues in embryogenesis, and is the causative factor in multiple congenital and adult diseases, including cardiovascular and limb defects, kidney disease, pulmonary hypertension, and is important in medical applications such as orthopedics, endodontics, and tissue engineering. BMP heterodimers have been shown to exhibit consistently higher signaling activity to BMP homodimers and thus are beginning to be used in therapeutics. Understanding how BMP heterodimers signal more effectively or exclusively in some contexts, will lead to their more successful use in applications like tissue engineering, bone repair and regeneration. The zebrafish offers a paradigm of exclusive BMP heterodimer signaling in patterning cells across the dorsoventral embryonic axis as a morphogen, with different levels specifying distinct cell types. This context will be exploited to test hypotheses for the more effective signaling by BMP heterodimers. Numerous extracellular modulators of BMP regulate its levels spatiotemporally in the embryo. Using phosphorylation of Smad5 (P-Smad5) as a direct readout of BMP signaling, a quantitative method will used to determine how these extracellular factors shape the signaling gradient in space and time. How P-Smad5 translates the gradient into distinct gene expression domains that specify cell fate will also be addressed. In most vertebrates, polarity of the egg determines anterior-posterior polarity of the embryo and is essential to establishing the embryonic dorsal-ventral axis. Egg polarity originates during early stages of oogenesis when distinct animal-vegetal domains are established in the oocyte. The first polarized structure in vertebrate oocytes is the Balbiani body (Bb), a large, membrane-less structure conserved from insects to mammals that in frogs and fish is composed of ribonucleoproteins, ER, golgi, an enrichment of mitochondria, and RNAs destined to the vegetal pole of the oocyte and egg. The Bb is a transient structure that dissociates at the oocyte cortex delivering its contents and determining the vegetal pole. Although fundamental to forming the major axes of most vertebrate embryos, vertebrate oocyte polarity has been little studied due to the inaccessibility of these early oocyte stages within the ovary and the difficulty of genetic analysis in adult females. Through a mutant screen in the zebrafish, two genes were discovered that establish oocyte polarity, bucky ball (buc) and macf1 (microtubule actin crosslinking factor 1). Buc is required to form the Bb, whereas Macf1, an unusually large cytoskeletal linker protein, is required for its dissociation. Buc is a highly disordered protein that can undergo a phase transition to form amyloid-like fibers in vitro. The role of these proteins in aggregating the Bb and dissociating it will be studied. Two newly identified Bb resident proteins will be investigated for their functions in Bb formation and its dissociation. Importantly, inappropriate amyloid protein aggregates in cells are hallmarks of neurodegenerative disease. Thus, these studies are relevant to understanding how these aggregates form and can be dissociated in therapeutics.

骨形态发生蛋白 (BMP) 信号传导指导多个器官和组织的发育 胚胎发生，是多种先天性和成人疾病（包括心血管疾病）的致病因素 和肢体缺陷、肾脏疾病、肺动脉高压，并且在医疗应用中很重要，例如 骨科、牙髓病学和组织工程。 BMP 异二聚体已被证明表现出一致的 BMP 同二聚体具有更高的信号传导活性，因此开始用于治疗。理解 BMP 异二聚体如何在某些情况下更有效或更专门地发出信号，将导致它们更有效 成功应用于组织工程、骨修复和再生等应用。斑马鱼提供了 跨背腹胚胎轴的模式细胞中唯一的 BMP 异二聚体信号传导范例 形态发生素，不同水平指定不同的细胞类型。该上下文将被用来测试 BMP 异二聚体的更有效信号传导的假设。多种 BMP 细胞外调节剂 调节其在胚胎中的时空水平。使用 Smad5 (P-Smad5) 的磷酸化作为直接 读出 BMP 信号传导，将使用定量方法来确定这些细胞外因子如何形成 空间和时间上的信号梯度。 P-Smad5 如何将梯度转化为不同的基因表达 指定细胞命运的领域也将得到解决。在大多数脊椎动物中，卵的极性决定了 胚胎的前后极性对于建立胚胎背腹轴至关重要。蛋 极性起源于卵子发生的早期阶段，当时不同的动植物域建立在 卵母细胞。脊椎动物卵母细胞中第一个极化结构是巴尔比亚尼体 (Bb)，它是一个大的、无膜的 从昆虫到哺乳动物，青蛙和鱼类中都保守的结构，由核糖核蛋白、ER、 高尔基体，线粒体的富集，以及运往卵母细胞和卵子植物极的RNA。 BB 是 在卵母细胞皮质处解离的瞬时结构，传递其内容物并确定植物 极。尽管对于形成大多数脊椎动物胚胎的主轴至关重要，但脊椎动物卵母细胞极性 由于卵巢内这些早期卵母细胞阶段的不可接近性和困难性，对此进行的研究很少 成年女性的遗传分析。通过对斑马鱼的突变筛选，发现了两个基因： 确定卵母细胞极性、巴基球 (buc) 和 MACF1（微管肌动蛋白交联因子 1）。需要 Buc 形成 Bb，而 Macf1（一种异常大的细胞骨架连接蛋白）是其解离所必需的。 Buc 是一种高度无序的蛋白质，可以在体外经历相变形成淀粉样蛋白纤维。这 将研究这些蛋白质在 Bb 聚集和解离中的作用。两名新确定的 Bb 居民 将研究蛋白质在 Bb 形成及其解离中的功能。重要的是不合适 细胞中淀粉样蛋白聚集是神经退行性疾病的标志。因此，这些研究是 与理解这些聚集体如何形成以及如何在治疗中解离相关。