CONTROL OF EARLY EYE DEVELOPMENT BY BMP'S

通过 BMP 控制早期眼睛发育

• 批准号: 6342683
• 负责人: YASUHIDE FURUTA
• 金额: $ 22.75万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-01-01 至 2004-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6342683
• 关键词: bone morphogenetic proteins; early embryonic stage; embryogenesis; eye; fibroblast growth factor; genetic manipulation; genetically modified animals; growth factor receptors; in situ hybridization; laboratory mouse; optic disk; protein structure function; transfection

The long term goal of this proposal is to define the roles of Bone Morphogenetic Proteins (BMPs), members of the TGF- superfamily of secreted signaling molecules, during mammalian eye development. BMPs have been implicated in many aspects of embryonic inductive tissue interactions. In particular, we have recently shown that one family member, Bmp4, plays an essential role during lens induction in the mouse embryo. In recent studies, chromosomal deletions in humans at 14q22- q23, where the BMP4 gene is mapped, have been linked with dominant anopthalmia and pituitary hypoplasia. Moreover, it has been shown that another family member, Bmp7, is required for normal eye development in the mouse. However, the molecular mechanisms by which BMPs regulate specific processes in vertebrate eye development are poorly understood. Here, we propose genetic and experimental embryological approaches to address this question, focusing on the roles of Bmp4 and a type-I Bmp receptor, Alk3. We will test the following three hypotheses; (1) that Bmp4 function is required, not only during lens induction, but also during subsequent steps in eye formation, (2) that Bmp4 and another signaling factor, Fgf15, directly mediate the lens inductive signal of the optic vesicle, (3) and that Bmp signaling is required independently in both the lens ectoderm and the retinal neuroectoderm during early eye development. Our strategy utilizes an embryonic eye explant culture technique we have established. We will treat both mutant and wildtype embryonic eye tissues with exogenous Bmp4 and/or Fgf15 proteins to explore their functions in eye formation. Furthermore, we will generate mouse embryos that lack Alk3 receptor function specifically in the developing eye using the Cre-loxP system for conditional gene disruption. The original homozygous AIk3 mutation causes pre-gastrulation embryonic lethality, and therefore the eye specific gene disruption is crucial for studying function of this gene during embryonic eye development. The embryos generated by this technique will provide mutant eye tissues which will be used for recombination organ cultures to study tissue-type specific functions of BMP signaling. These studies will contribute significantly to our understanding of the fundamental roles of secreted signaling molecules in mammalian eye development. Moreover, the results will shed light on the possibility that abnormal regulation of intercellular signaling contributes to congenital eye defects and associated postnatal eye dysfunctions in humans.

这项提案的长期目标是确定骨形态发生蛋白（BMP）的作用，分泌信号分子的TGF-超家族的成员，在哺乳动物的眼睛发育。BMP在胚胎诱导组织相互作用的许多方面都有牵连。 特别是，我们最近已经表明，一个家庭成员，Bmp 4，在小鼠胚胎透镜诱导过程中起着至关重要的作用。在最近的研究中，人类染色体14 q22- q23（BMP 4基因定位的位置）的缺失与显性无眼症和垂体发育不全有关。 此外，已经表明另一个家族成员Bmp 7是小鼠正常眼睛发育所必需的。 然而，骨形成蛋白调节脊椎动物眼睛发育的特定过程的分子机制知之甚少。在这里，我们提出了遗传和实验胚胎学的方法来解决这个问题，集中在BMP 4和I型BMP受体，Alk 3的作用。我们将测试以下三个假设：（1）不仅在透镜诱导期间，而且在眼睛形成的后续步骤期间，都需要Bmp 4功能，（2）Bmp 4和另一种信号传导因子Fgf 15直接介导视泡的透镜诱导信号，（3）并且在早期眼发育期间，在透镜外胚层和视网膜神经外胚层两者中独立地需要Bmp信号传导。我们的策略利用我们已经建立的胚胎眼外植体培养技术。我们将用外源性Bmp 4和/或Fgf 15蛋白处理突变型和野生型胚胎眼组织，以探索它们在眼形成中的功能。此外，我们将使用Cre-loxP系统进行条件性基因破坏，产生在发育中的眼睛中特异性缺乏Alk 3受体功能的小鼠胚胎。原始纯合AIk 3突变导致原肠胚形成前胚胎死亡，因此眼特异性基因的破坏对于研究该基因在胚胎眼发育中的功能至关重要。通过该技术产生的胚胎将提供突变的眼组织，其将用于重组器官培养以研究BMP信号传导的组织类型特异性功能。这些研究将有助于我们了解分泌的信号分子在哺乳动物眼睛发育中的基本作用。此外，这些结果将揭示细胞间信号的异常调节导致人类先天性眼缺陷和相关的出生后眼功能障碍的可能性。