MCA: Defining the role of the small GTPase Rap1 in a slow cell intercalation event in the Drosophila melanogaster eye

This project will probe the role of a protein called Rap1 in the mechanisms that drive morphogenesis: the changes in cell and tissue shapes and arrangements that occur during development of all animals, and that are essential for their form and function. The Curtiss lab has laid the groundwork for this project by employing a combination of molecular genetics and conventional microscopic approaches on preserved tissues. However, as morphogenesis is a dynamic process that occurs in minutes to hours, it is essential to visualize these processes in living tissues. Dr. Curtiss will collaborate with Dr. Franck Pichaud at University College London to learn state-of-the-art live-cell imaging and how to measure biological and mechanical properties during morphogenesis in eyes of fruit flies. Although a lot has been learned in recent years about the mechanisms that drive morphogenesis of cells and tissues, much of this work has been done on a few relatively simple organisms containing very similar cell types. This project will examine morphogenesis in a tissue containing multiple cell types, to understand how they can work together to promote morphogenesis of the whole tissue. Dr. Curtiss will bring knowledge of these state-of-the-art techniques and measurements back to New Mexico State University. With advice from Dr. Pichaud at University College London and from Dr. Charles Shuster at New Mexico State University, Dr. Curtiss will train graduate and undergraduate students in these techniques, which will enrich their educations and give them the skills needed to compete at top levels in future research endeavors. Recent years have seen remarkable advances in understanding of cell intercalation in morphogenesis. These insights stem from equally remarkable advances in live-cell imaging, careful measurements of cell shape, adhesion, and contractility, as well as mathematical modeling. Most current models focus on fast cell intercalation (occurring in minutes) in homogeneous cell populations. Using conventional immunofluorescence, the Curtiss lab has discovered a role for the small GTPase Rap1 in a slow cell intercalation of cone cells that occurs over hours and with influence from multiple cell types during pupal eye development in Drosophila melanogaster. Dr. Franck Pichaud has developed live-cell imaging and mathematical modeling approaches to understanding this same morphogenetic event. The goals of this project are for Dr. Curtiss to travel to Dr. Franck Pichaud’s lab at University College London to learn and apply: 1) Live-cell imaging to determine whether Rap1 affects cell adhesion molecule localization, Notch signaling, and/or Myosin II localization during cone cell intercalation, and; 2) Quantitative analyses and use of vertex models to determine the effects of Rap1 on previously measured biomechanical properties during cone cell intercalation. Dr. Curtiss will bring these new techniques back to her lab at New Mexico State University, and, with help from Dr. Pichaud at University College London and from Dr. Charles Shuster at New Mexico State University, will instruct her graduate and undergraduate students in these techniques. Achieving these goals will contribute to existing knowledge about morphogenesis in all animals and will enable students to compete at top levels in their future research endeavors. This project is jointly funded by the NSF/BIO/MCB Cell Dynamics & Function Program and the NSF Established Program to Stimulate Competitive Research (EPSCoR). 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.