Tamily A. Weissman - US grants

An award is made to Lewis & Clark College (L&C) in Portland, Oregon to acquire a Zeiss LSM 710 Confocal Microscope, which will enable at least six different laboratories on campus (in Biology, Chemistry, and Physics Departments) as well as two collaborating labs at other institutions (in Molecular Biosciences and Neurology Departments) to expand and innovate their existing research programs. Confocal microscopy is an advanced fluorescence imaging technique that has a number of advantages over traditional fluorescence microscopy and is a particularly powerful tool for live imaging experiments. The enabled projects focus on live imaging, both in whole organisms (zebrafish, nematode, yeast) and in cultured neurons (mouse). Some of these include: 1) a powerful multicolor approach (Brainbow) to test how newborn cells in the immature brain transform into organized neuronal circuits; 2) fluorescence resonance energy transfer (FRET) to study interactions among ribosomal components in yeast; 3) photoconvertible proteins to study the regulated release of factors in hippocampal neurons during neuronal activity; and 4) in vivo imaging techniques in living zebrafish to study the behavior of proteins that underlie Parkinson's Disease in humans. The principal investigators have externally funded, active research programs that engage undergraduate students as partners in data generation and publications in peer-reviewed journals. Acquisition of a confocal microscope will help these laboratories to generate high-quality publications in areas that utilize and develop cutting-edge live imaging approaches.

The confocal acquisition will also have a number of important broader impacts. First, future generations of scientists will have the opportunity to master modern imaging approaches during their undergraduate training. Many L&C students go on to Ph.D. programs and careers in science after winning competitive research fellowships. In part this can be attributed to L&C's strong focus on involving undergraduates in meaningful research; in the past five years, more than 90 undergraduate students have contributed as co-authors on publications. These dedicated and capable students will become trained in advanced microscopy by using the confocal system in their coursework and/or research laboratory. Second, L&C is a leader in the training of groups that are traditionally underrepresented in science. The natural sciences at L&C boast large numbers of women majors. In addition, L&C runs a successful, HHMI-funded summer research program that brings high school students from under-represented groups to campus for an intensive, 8-week laboratory experience. The confocal microscope will thus impact large numbers of young women who have chosen to pursue a career in science, as well as high school students who are just beginning to consider the direction of their future training. The opportunity to conduct live imaging experiments is often inspiring for students at this critical stage in their career path. Finally, the L&C Watzek Library Digital Initiatives staff will help design and construct an online public gallery that will showcase selected images and videos captured using the confocal microscope. The funded equipment thus has the potential to impact the broader community and to increase scientific literary among the public

The remarkable function of the brain requires proper growth and formation in the embryo. First, a small cluster of cells increases dramatically in number, then transforms into an exquisitely organized organ with a complicated pattern of connections. Most of the time, this process results in brains that are perfectly normal, with the right number of nerve cells. Surprisingly little is known, though, about how the growing brain decides how many cells to produce. This research project will look at the control of cell number in the growing brains of transparent living zebrafish during the first few days of life. The PI has developed techniques for watching clusters of dividing cells over time in special zebrafish embryos whose brain cells glow with unique combinations of colors (called "Brainbow"). This coloring allows new cells to be followed as they divide off from their mother cell. So far it appears that families of cells (mother cell with her set of daughter cells) compete with other families to survive in the growing brain. This type of competition has not been seen before in the brain, and may be responsible for controlling growth - not only in the brain, but in other organs as well. The PI will test which genes are important for cell families to survive this competition. The work will generate a number of new research tools that will be shared with the scientific community. Undergraduate students will perform and analyze the experiments themselves, providing rich opportunities for research training early in developing scientists' careers. By also transforming the data they have personally collected into an interactive, educational website, students will learn various digital media approaches to making scientific material understandable to traditional and non-traditional audiences. The colorful images produced by this research have great appeal to both scientists and non-scientists, making it easier for students to learn how to engage the public with their work.

To study dynamic cellular behavior in the living brain, the PI has developed an approach using in vivo time-lapse confocal imaging and multicolor fluorescent protein (Brainbow) expression in zebrafish. Using this technique, the PI has shown that programmed cell death occurs non-randomly in the living brain, with specific neural progenitor cells and their neuronal progeny (entire clones) undergoing cell death in a coordinated manner, while neighboring clones appear normal. If whole clones of dividing cells are in fact competing with one another, increases or decreases in cellular fitness should influence a clone's competitive edge. The planned research will use a mosaic approach to alter gene expression in individual cells, coupled with global Brainbow expression to simultaneously follow dynamics within multiple clones of dividing cells. Cellular fitness will be targeted via both cell-intrinsic mechanisms (cell cycle, c-myc activity) and cell-extrinsic mechanisms (access to extracellular BMP signaling). These experiments will test directly whether cellular fitness influences a clone?s ability to survive in the developing brain. Overall this may support the hypothesis that competition among clones of dividing cells helps regulate neuronal production and growth in the developing nervous system.