CAREER: PROTEIN-PROTEIN INTERACTIONS DRIVING THE EVOLUTION OF GENE REGULATION

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

Terrestrial ecosystems are dominated by flowering plants, and humans are dependent on the ultimate products of flower development - fruits and seeds. Flowers are extremely diverse in shape and form, yet flower development is controlled by the same core set of transcription factors (proteins that control gene expression). To resolve this paradox, it has been hypothesized that changes in how genes are controlled by these core transcription factor genes has been critical in the evolution of flowering plant diversity. The goal of this project is to test this hypothesis. This project will uncover the molecular underpinnings of floral diversification, and provide key insight into the molecular biology of floral development in the economically important grass family, which includes corn and wheat. An educational program will be developed for students from high school to graduate levels. High school students, especially women, will learn basic molecular biology by working in the investigator's lab in the summers. Undergraduates will be trained in the theory and techniques of molecular biology and molecular evolution in a lab-based class and independent research. Graduate students will be involved in all aspects of the research and outreach. Trainees at all levels will be involved in all stages of the scientific process, from experimental design to publication. The educational program will provide students with the practical skills and scientific understanding fundamental to success as part of the US workforce. The floral MADS-box transcription factors are critical regulators of flower development across angiosperms. A long-standing hypothesis is that evolutionary change in flower form can be driven by shifting interactions between floral MADS-box transcription factors that go on to affect downstream gene regulation. This project will test this hypothesis using an experimental system developed by the PI, where MADS-box protein-protein interactions can be precisely manipulated to study how they impact downstream gene expression and floral development. In Aim 1, the impact of evolutionary variation in MADS-box dimerization on floral development will be explored using gene editing technology, microscopy, and geometric morphometrics. In an allied education aim, high school interns will assist with genotyping plant lines, and explore the people behind the science in a 'Heroes of Biology' journal club. In Aim 2, the genome-wide gene expression profiles downstream of evolutionary variation in MADS-box dimerization will be determined using RNA-Seq and ChIP-Seq. In an allied education aim, undergraduates in the lab will design and perform qRT-PCR experiments to validate next-generation sequencing results. In Aim 3, the protein-protein interaction profiles of MADS-box dimer variants will be determined both in vitro and in planta. Sophomores in the PI's research-based molecular evolution class will test select MADS-box protein-protein interactions. This project will contribute to the understanding of regulatory evolution, to the understanding of floral diversity, and to the understanding of floral development. The mechanistic understanding of grass flower development gained through this work, including in a major crop plant (maize), may facilitate the precise manipulation of floral development for enhanced plant productivity.