Audrey J. Ettinger, Ph.D. - US grants

The development of six distinct classes of neurons and one class of glia in the vertebrate retina requires a complex interplay of cell-intrinsic and cell-extrinsic molecular events. The experiments proposed here will utilize the powerful system of the teleost retina to establish the specific roles and relative hierarchy of molecules reported to function in the development of rod photoreceptors. Since the teleost retina adds new neurons and glia throughout its life, all stages of retinal development are present concurrently. The first set of proposed experiments are designed to discover the hierarchy of expression of a set of transcription factors expressed in the course of rod photoreceptor development. Following their description, overexpression and blocking experiments will establish the role of each factor in controlling rod neurogenesis. The second set of experiments will define the role of secreted growth factors in rod photoreceptor development. Soluble factors including CNTF, EGF, and TGFalpha will be applied to retinal slices and their effects on cell division and differentiation measured. Application of antibodies to block the function of each molecule will further help to elucidate their function. The transcription factors and growth factors present in the teleost retina are found in most vertebrates, including humans. Understanding the mechanisms that cause a dividing progenitor cell to become a particular kind of neuron may become useful in treating human disease, particularly since stem cells have recently been identified in the mammalian central nervous system and human embryonic stem cells have been isolated.

For the past three years, students involved in the Molecular Genetics course have collaborated with students from either the Developmental Biology or Diseases of the Nervous System courses to conduct a research-based, multi-week project using microarrays to measure changes in gene expression in chicken embryos or neurons following chemical exposure. Chicken microarrays were obtained from and scanned by the Genome Consortium for Active Teaching (GCAT), a project geared towards motivating undergraduate research, formerly sponsored by the Howard Hughes Medical Institute. To continue the cross-course collaboration and give students access to newer techniques, the current project switches to an alternative, more current technology, PCR-based arrays, and adds electrophysiology and qPCR to enable follow-up confirmatory studies and extend student learning. This effort has three foci: 1) redesign of lab activities to incorporate the use of PCR arrays, electrophysiology, and other molecular techniques to study altered gene expression levels, 2) inclusion of faculty at neighboring institutions to reach additional first generation and minority students, and 3) dissemination of lab protocols to other institutions as a viable methodology for teaching development, neuroscience, and molecular biology in college lab courses.

Intellectual Merit: The initial project increased the learning gains of students across the biology sub-disciplines by engaging them in the process of discovery. Participating students in the current courses are gaining skills in experimental design, collaborative research, use of multiple technology platforms, and data presentation.

Broader Impacts: At the national level a large number of institutions that relied on the GCAT program are now seeking to fill the gap left by the termination of that resource. The new approaches being developed by this project offer important alternative strategies to the GCAT-user community.

This project is being jointly funded by the Directorate for Biological Sciences and the Directorate for Education and Human Resources, Division of Undergraduate Education as part of their efforts toward support of Vision and Change in Undergraduate Biology Education