The Laboratory of Bruce Edgar is located at the Fred Hutchinson Cancer Research Center, in the Division of Basic Sciences, in Seattle, Washington. Graduate studies in the Edgar lab may be done through the Molecular and Cellular Biology program of the University of Washington and FHCRC.

Growth Regulation During Drosophila Development

Metazoan cells typically exist in a physiologically controlled environment that is always nutrient rich, yet they proliferate selectively. Specific signals from other cells stimulate or limit their growth and proliferation according to rules that benefit the organism as a whole. The division of animal cells is not always growth-coupled. Some cell types, like neurons and oocytes, grow without dividing while others, such as spermatocytes, early blastomeres and neuroblasts, can divide many times with little or no growth. Thus the controls for cell growth and cell cycle progression, while overlapping, are not the same. The goal of our research is to understand some of the genetic logic ? or regulatory "circuitry" - that controls cell growth and coordinates it with cell cycle progression in Drosophila. The signaling systems that regulate tissue growth and patterning have been intensively studied in this system, as have mechanisms of cell cycle control. How these signaling systems regulate cell growth, and the relationship of growth to proliferation, however, remain areas of ignorance.

Our approach is to identify genes that act as specific, dedicated regulators of cell growth, and then determine how they are controlled, upstream, by genetic programming and cell signaling and how, downstream, they alter cell metabolism to regulate cell growth and the cell cycle. In the lab, we make extensive use of classical and molecular genetics, mosaic analysis, quantitative cytological assays of growth and proliferation, and gene expression profiling. We hope to define new genes and mechanisms involved in growth control that will impact general paradigms in cell and developmental biology, and which also have relevance to medical conditions involving cell and tissue growth including cancer diagnosis and therapy, regeneration, wound healing, diabetes and other metabolic diseases.

Current projects include:

• Genetic analysis of cell cycle control in the imaginal wing.
• Mechanism of the endocycle.
• Growth-regulatory targets of Cyclin D/Cdk4.
• Functional analysis of rheb, a novel growth driver acting in insulin/Tor signaling.
• The role of regulated rRNA synthesis in growth control.
• dMyc as a mediator of patterned growth control.
• Nutritional control of cell growth in the polyploidy larval cells.
• Ubx and Dpp as regulators of wing growth.