Role of Pitx3 signaling cascades in the regulation of Xenopus eye, laterality and somite development

Pitx3信号级联在非洲爪蟾眼睛、侧向性和体节发育调节中的作用

• 批准号: RGPIN-2018-03995
• 负责人: Crawford, Michael
• 金额: $ 2.33万
• 依托单位: University of Windsor
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=648268
• 关键词: Role; Pitx3; signaling; cascades; regulation

We started by studying the network of genes that contribute to normal eye development and maintenance, specifically the role of a regulatory gene, pitx3, in the formation of lens. Our interests expanded to visceral organ asymmetry and vertebral development when it became apparent that pitx3 plays a role in these aspects of development too. This gene is linked to eye and neurological deficits in mice and humans. The preservation of nearly identical roles for this gene in eye, and in eye gene networks, means that experiments in organisms such as frog offer big benefits to understanding development in mammals such as ourselves. For example, frog embryos develop externally (no uterus to get in the way of observation and experimentation), they can be easily manipulated surgically or genetically, and the century-long eye studies in amphibians have pioneered and clarified our understanding of how eyes develop in human. ******In our studies of pitx3, we previously showed how it plays a primary role in the formation of lens, which is in turn critical to formation of the retina. The absence of frog pitx3 activity, no lens forms, and retinal development is either impaired or prevented. We then developed a new procedure to examine how this gene regulates others in the network of genes that build an eye. Our system works with exquisite sensitivity to reveal gene regulatory changes on a cell-by-cell basis: we identified some new and important players that are regulated by pitx3, but that are not yet well understood in human eye development. ******A curious feature of pitx3 function is that it can turn target genes on or off in a context-dependent manner. Our proposal is to look for pitx3-interacting partners that might explain this flexibility. Moreover, by cataloging the interacting partners (interactome) of pitx3, we might come to understand: how it affects development of vertebral precursors and heart; whether there are differences in partner availability and timing between humans and frogs; and we might identify new partners with mammalian relatives. For example, since one of the mutational effects of pitx3 is to produce lens cataracts, and pitx3 activates at least one of the genes that provides the bulk of protein constituting and defining the clarity of lens (a beta-crystallin gene), our proposal to identify interacting partners will improve our understanding and reveal some of the mechanisms that underly cataract formation. An additional feature of pitx3 activity is that in frog, it plays a role in defining the asymmetry of some of the visceral organs such as heart, gastro-enteric tract etc. Pitx3 dysfunction results in inversion of organ placement, e.g.; patterning defects of heart, vasculature, and gut. Since related genes play a role in organ asymmetry in human, our search for interacting partners in frog has potential to illuminate new avenues for investigation of human congenital heart defects.

我们从研究有助于正常眼睛发育和维持的基因网络开始，特别是调节基因pitx 3在透镜形成中的作用。我们的兴趣扩展到内脏器官的不对称性和脊椎发育，当它变得明显，pitx 3在这些方面的发展也发挥作用。这种基因与小鼠和人类的眼睛和神经缺陷有关。这种基因在眼睛和眼睛基因网络中的作用几乎相同，这意味着在青蛙等生物体中进行的实验对理解我们人类等哺乳动物的发育有很大的好处。例如，青蛙胚胎在外部发育（没有子宫妨碍观察和实验），它们可以很容易地通过手术或基因进行操作，长达一个世纪的两栖动物眼睛研究开创并澄清了我们对人类眼睛如何发育的理解。** 在我们对pitx 3的研究中，我们先前展示了它如何在透镜的形成中发挥主要作用，而透镜又对视网膜的形成至关重要。青蛙pitx 3活性的缺失、透镜的形成和视网膜发育受损或被阻止。然后，我们开发了一种新的程序来研究这种基因如何调节构建眼睛的基因网络中的其他基因。我们的系统以极高的灵敏度工作，以逐个细胞的方式揭示基因调控变化：我们确定了一些新的重要参与者，这些参与者受到pitx 3的调控，但在人类眼睛发育中尚未得到很好的理解。** pitx 3功能的一个奇怪特征是，它可以以上下文依赖的方式打开或关闭靶基因。我们的建议是寻找可能解释这种灵活性的pitx 3交互伙伴。此外，通过对pitx 3的相互作用伙伴（相互作用组）进行编目，我们可能会了解：它如何影响脊椎前体和心脏的发育;人类和青蛙之间是否存在伙伴可用性和时间的差异;我们可能会与哺乳动物亲属确定新的伙伴。例如，由于pitx 3的突变效应之一是产生透镜白内障，并且pitx 3激活至少一个基因，该基因提供构成和限定透镜透明度的大量蛋白质（β-晶状体蛋白基因），因此我们鉴定相互作用伴侣的提议将提高我们的理解并揭示白内障形成的一些机制。pitx 3活性的另一个特征是，在青蛙中，它在定义某些内脏器官如心脏、胃肠道等的不对称性中起作用。心脏、脉管系统和肠道的模式化缺陷。由于相关基因在人类器官不对称性中起作用，我们在青蛙中寻找相互作用的伴侣有可能为人类先天性心脏病的研究开辟新的途径。