Collaborative Research: Uncovering Principles Underlying Rod Photoreceptor Outer Segment Renewal and Size

光感受器是在出生前和出生后不久形成的神经细胞，如果它们退化了，就不能被替换。感光细胞的感光天线是细胞的基本特征，必须不断刷新(或再生)才能最佳地捕捉光线。如果没有这种天线，感光细胞就不能感知光线，感光细胞就会死亡，导致失明。这种持续的再生是通过在其底部添加新产生的蛋白质和膜，以及通过从其顶端脱落最古老的蛋白质和膜来实现的。值得注意的是，感光细胞能够在生长和脱落的动态过程中保持其天线的恒定长度。该项目的目标是发现眼睛中光感受器细胞用来确定其天线长度的规则。除了了解这一至关重要的再生过程外，这项建议还将使新一代STEM学者能够学习在STEM学科中蓬勃发展至关重要的技能。特别是，一批学生、本科生和研究生将参与这项研究，并在数学/计算机建模和生命科学方面获得重要的培训和指导。该项目还纳入了一些活动，以增加未被充分代表的群体目前和未来在STEM教育和职业中的参与度。该项目旨在发现感光细胞用来计算和平衡其感光天线中蛋白质和膜的生长和脱落速率以保持其细胞天线的恒定长度的规则。利用基因操作的斑马鱼揭示感光器天线中的动态再生过程，将发现规律。其中一组实验旨在刺激底部的额外生长，结果将揭示天线长度是否增加，或者脱落是否增加以平衡额外的生长速度以保持长度不变。设计了另一组实验，其中尖端的脱落将被阻止，结果将揭示天线长度是否会由于被阻止的脱落而增加，或者底部的增长是否放缓以平衡尖端的额外长度以保持长度恒定。最后，将建立数学模型来预测实验操作后光感受器天线的长度。这些模型是基于我们目前对生长和脱落的理解，其中模型输出将与天线长度的实验数据进行匹配/比较。这种模型的美妙之处在于，它可以用来帮助揭示(甚至预测，与未来的实验一起)光感受器用来维持感官天线恒定长度的调节机制。这项提议的结果将作为未来努力定义光接收器中的细胞机制的重要基础，该机制有助于其光敏天线的关键再生过程。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Photoreceptors are neuronal cells that form before and soon after birth, and cannot be replaced if they degenerate. The light-sensing antenna of photoreceptor cells is an essential feature of the cells and must be continuously refreshed (or regenerated) in order to optimally capture light. Without this antenna, photoreceptor cells cannot sense light, and the photoreceptor cells die, resulting in blindness. This continuous regeneration occurs by the addition of newly produced proteins and membranes at its base and by the shedding of the oldest proteins and membranes from its tip. Remarkably, the photoreceptor cell is capable of keeping its antenna at a constant length, as the dynamic processes of growth and shedding occur. The goal of this project is to discover the rules used by photoreceptor cells in the eye to determine the length of their antenna. In addition to understanding this vital regeneration process, this proposal will allow a new generation of STEM scholars to learn the skills that are vital to thrive in STEM disciplines. In particular, a cohort of students, undergraduates and graduate students, will participate in the research and gain vital training and mentoring in mathematical/computer modeling and life science. This project also incorporates activities to increase current and future participation of underrepresented groups in STEM education and careers.This project seeks to discover the rules used by photoreceptor cells to calculate and balance rates of growth and shedding of proteins and membranes in their light-sensing antenna to maintain a constant length of their cellular antennas. Rules will be discovered using genetically manipulated zebrafish that reveal the dynamic regenerative process in the photoreceptor's antenna. One set of experiments is designed to stimulate extra growth at the base, and results will reveal whether antenna length increases or whether shedding increases to balance the extra growth rate to maintain a length constant. Another set of experiments is designed in which shedding from the tip will be blocked, and results will reveal whether antenna length will increase due to blocked shedding or whether growth at the base slows to balance the extra length at the tip to maintain a length constant. Finally, mathematical models will be developed to predict the length of photoreceptor antenna following experimental manipulation. Such models are based on our current understanding of growth and shedding, where model output will be fit/compared to experimental data of antenna length. The beauty of such a model is that it can be used to help reveal (and even predict, alongside with future experiments) the regulatory mechanisms that photoreceptors use to maintain the constant length of their sensory antennas. The outcomes of this proposal will serve as an important foundation for future efforts to define the cellular machinery in photoreceptors that contribute to the critical regenerative process of their light-sensing antenna.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.