Bioelectrical Controls of Morphogenesis

描述（由申请人提供）：脊椎动物体型的一致左右（LR）不对称性是发育和进化生物学的一个迷人的难题，对生物医学具有深远的影响。偏侧性缺陷影响超过1/6000的足月出生婴儿，分子细节对于理解，检测，预防和修复与LR模式错误相关的出生缺陷至关重要。该领域目前处于混乱状态，缺乏概念模型，可以将小鼠和斑马鱼胚胎LR模式的机制与在非洲爪蟾中发现的更早的机制联系起来。我们最近的工作已经确定了全新的离子流依赖性事件，在早期LR模式的功能和保守的青蛙，小鸡，和斑马鱼。然而，现有的模型没有解释如何电压梯度可以可靠地定向相对于LR轴在小鸡和哺乳动物的身体计划。令人兴奋的数据表明，内源性电压和pH梯度产生的离子通道和泵依赖性电流在细胞和组织中调节胚胎发育和再生的一些重要的形态发生事件。最近的爆炸性工作集中在基因转录网络和分泌的信号传导因子在很大程度上忽略了这些迷人的表观遗传生物物理现象。我们的实验室结合了分子和细胞生物学，生物物理学，生理学和计算机建模的强大现代工具;因此，我们的工作不仅有助于理解左右模式，而且还揭示了内源性离子流如何控制细胞行为的新分子细节。我们的方法和试剂提供了一个有价值的和独特的机会来解决主要的难题，即在与胚胎中线对齐的大卵裂球中建立不对称性的细胞质事件如何在其他动物（如哺乳动物）中发挥作用，而这些动物中存在许多小细胞。我们将解决这个难题，通过解决主要的悬而未决的问题，通过（1）确定3个特定的离子转运蛋白是如何参与强加LR不对称到大细胞领域的自主“组织者”的焦点，（2）表征极性和细胞骨架蛋白的相互作用，在控制本地化和/或行为的离子通量在细胞中。总之，这些实验利用了一套强大的方法，在一个模型系统（非洲爪蟾）适合分子遗传学和功能生物物理学。通过利用我们已经获得的令人兴奋的初步和已发表的数据，我们的工作将揭示可用于深入了解形态发生的细胞和进化生物学的新机制，将该领域与主流分子发育生物学相结合，并最终成为针对出生缺陷，再生和肿瘤生物学许多领域的新方法的基础。

DESCRIPTION (provided by applicant): The consistent left-right (LR) asymmetry of the vertebrate bodyplan is a fascinating puzzle of developmental and evolutionary biology, and has profound implications for biomedicine. Laterality defects affect more than 1 in 6000 babies born to term, and the molecular details are crucial to understanding, detection, prevention, and repair of birth defects related to errors of LR patterning. The field is currently in disarray, lacking conceptual models that can link mechanisms uncovered for the LR patterning of mouse and zebrafish embryos to the much earlier mechanisms that have been discovered in Xenopus. Our recent work has identified completely novel ion flow-dependent events that function in early LR patterning and are conserved to frog, chick, and zebrafish. However, the existing models do not explain how voltage gradients can be reliably oriented with respect to the LR axis in chick and mammalian body-plans. Exciting data indicate that endogenous voltage and pH gradients produced by ion channel and pump-dependent current flows in cells and tissues regulate a number of important morphogenetic events in embryonic development and regeneration. The recent explosion of work focused on gene transcription networks and secreted signaling factors have largely neglected these fascinating epigenetic biophysical phenomena. Our lab combines the powerful modern tools of molecular and cell biology, biophysics, physiology, and computer modeling; thus, our work will not only contribute to understanding left-right patterning but also reveal new molecular details of how endogenous ion flows control cell behavior. Our approaches and reagents present a valuable and unique opportunity to resolve the major puzzle of how early, cytoplasmic events that set up asymmetry in large blastomeres aligned with the embryo's midline may function in other animals (such as mammals) where many small cells exist instead. We will resolve this puzzle by addressing the major outstanding questions through (1) determining how 3 specific ion transporters are involved in the imposition of LR asymmetry onto large cell fields by foci of autonomous "organizers", and (2) characterizing the interaction of polarity and cytoskeleton proteins in controlling the localization and/or behavior of ion fluxes in cells. Together, these experiments take advantage of a powerful set of approaches in a model system (Xenopus) amenable to both molecular genetics and functional biophysics. By capitalizing on the exciting base of preliminary and published data that we have obtained, our work will reveal novel mechanisms that can be used to gain insight into the cell and evolutionary biology of morphogenesis, will integrate this field with mainstream molecular developmental biology, and will ultimately serve as the basis for novel approaches targeting many areas of birth defects, regeneration, and tumor biology.