Barbara Taylor - US grants

One important aspect of brain development is the generation of sex- specific neurons that are involved in the regulation of sex- specific behaviors, hormonal controls and reproduction. The development of male-specific and female-specific neurons will be studied in the fruitfly, an organism optimal for elucidating the genetic and molecular events underlying the development of neuronal fate. Immunohistochemistry and neuronal tracing techniques will be used to isolate and characterize male-specific and female-specific neurons in the nervous systems of both sexes. The effects of mutations on the commitment of neurons to a sex-specific fate and the maintenance of this decision will also be studied. These studies will provide fundamental information on genes involved in the generation of neuronal diversity in the brain.

9520849 TAYLOR Paleo-ecological reconstructions clarify long-term climatic patterns, explain current ecosystem structure, and predict ecological outcomes given certain changes in climate or management scenarios. The sequence of climatic changes affecting the development of natural wetland ecosystems of the Upper Atlantic Coastal Plain of the southeastern United States has not been well elucidated. The PI's propose to resolve this sequence of local climatic change by using the record of fossilized diatoms, sponge spicules, and plant phytoliths. These systems are attractive candidates for the research because they are non-fluvial precipitation basins whose sediments directly reflect local climate. The vertical sequence of microfossils and physical sediment components will be assessed in horizontal transects of sediment cores taken throughout several Carolina bays.

DESCRIPTION: The aim of this application is to characterize the role of dissatisfaction (dsf) and doublesex (dsx) in the expression of sexual behaviors by controlling differentiation of sex-specific neurons in Drosophila. Mutations in dsf affect female sexual behavior and altered sexual preference in males. In contrast, dsx appears to regulate the development of somatic tissues in the body. The proposed studies will use a combined molecular, genetic and anatomical approach to determine the expression of dsf or dsx in the nervous system, and to correlate the behavioral phenotype of the animal. Double or triple mutants of fru (fruitless), dsf and dsx, will also be constructed to investigating the genetic interaction. The proposed research will be testing the following hypothesis that three parallel pathways control the sexual development and behavior: the dsx gene controls the sexual development of somatic tissues in the body with little or no indirect role in sexual behavior; the dsf gene regulates female sexual behavior with auxiliary roles in some male sexual behavior; the fru gene controls only male sexual behavior.

9870396 TAYLOR Sexual development in the fruitfly, Drosophila melanogaster, is governed by a cascade of sex-determination genes. This cascade branches into three output pathways controlling mating behavior and the formation of the relevant sex-specific neurons in males and females. Each of the output branches is headed by a separate regulatory gene, "fruitless" (fru), "dissatisfaction" (dsf) or "doublesex" (dsx), which control distinct aspects of the sex-specific behavioral repertoire. fru controls all, or virtually all, aspects of male reproductive behaviors and the formation of a male-specific motorneuron that induces a sex-specific muscle, the Muscle of Lawrence (MOL). The sex-specific transcripts of the fru gene are expressed in a tiny fraction of neurons in the central nervous systems (about 0.5% of 100,000 neurons). The working model of fru action is that the fru-expressing neurons form dedicated neural circuits that direct other neurons to produce male-specific behaviors such as courtship song and copulation. The aim of this research is to characterize the role of the fru gene in specifying the male-specific motorneuron that innervates the MOL. In males, this neuron induces the formation of the male-specific MOL muscle, whereas in fru mutants, the motorneuron makes incorrect synapses and the male-specific characteristics of the MOL is not induced.
This POWRE award will allow Dr. Taylor to spend a year on sabbatical in the laboratory of Dr. Michael Bate at the University of Cambridge. She plans to investigate sex-specific differences in the physiology of the synapse between the MOL motorneuron and its target muscle in males versus the homologous synapse in females. A second goal of the project is to determine whether specific electrical activity in the motorneuron is required to induce the MOL. This project is particularly suitable for a POWRE award because Dr. Taylor will learn insect neurophysiology at one of the best laboratories for such studies. The introduction of this new approach and technical expertise will allow her to make scientific contributions to a wider audience than previously, which should, in turn, make her laboratory more visible and attractive to graduate students and postdoctoral researchers at a crucial point in her career.

DESCRIPTION (provided by applicant): Our previous studies led us to propose that a sex determination regulatory gene, fruitless (fru), is responsible for building the potential for male sexual behaviors into the CNS in D. melanogaster, and that the neural circuits underlying other complex innate behaviors are also likely constructed by the action of specific regulatory hierarchies (Baker, Taylor and Hall, 2001). Recently we showed that the FruM proteins are both necessary and sufficient to specify the potential for male courtship behavior. Moreover, the FruM proteins are expressed exclusively in subsets of the CNS and the primary sensory neurons of all sensory systems implicated in courtship. Expression is maximal about two days into the pupal period, when ca. 2000 cells (~2% of neurons) express FruM proteins. Strikingly, these neurons are dedicated to sexual behaviors, as inactivating them has no discernable effects other than on sexual behaviors. The findings that FruM proteins are expressed in only a small portion of the nervous system that is dedicated to sexual behavior, and are necessary and sufficient for nearly all aspects of sexual behavior are provocative and pleasing. They suggest FruM provides a handle for dissecting the developmental, genetic, molecular, and neuronal bases of male courtship behavior. We believe the key to gaining an understanding of how (1) the potential for a complex behavior is built into the nervous system, and (2) the neurons subserving male courtship behavior function together to insure the ordered manifestation of the events comprising this behavior, will be to focus on the groups of neurons in which the FruM proteins are expressed. On-the-one-hand we address how the FruM transcription factors shape the anatomical and molecular characteristics of these neurons. On-the-other hand we address the roles of individual groups of these neurons in the complex set of behaviors that comprise male courtship. Thus this grant focuses on the roles that these neurons play in adult male sexual behavior, and the fru-dependent characteristics that distinguish them. A long-term goal is to elucidate the structure of the FruM-specified courtship circuitry and how it functions. Central to our approach is the development of fru-based genetic tools that permit the manipulation of FruM-expressing neurons without affecting other neurons. Such constructs allow visualization of the nuclei of FruM-expressing neurons and their projections, silencing of these neurons, changing the sex of these cells from male to female or from female to male, suppression of FruM synthesis in targeted neurons. Thus we can functionally manipulate a discrete group of FruM neurons and behaviorally assess its effects on the execution of male courtship. We can also use these tools to identify the neuroanatomical and molecular characteristics of neurons that are specified by FruM. These studies will provide a model for how the circuitries underlying other innate behaviors are built and function. PUBLIC HEALTH RELEVANCE Our research promises to yield an unprecedented, detailed view of the molecular, cellular and behavioral basis for gender differences in the model genetic organism Drosophila melanogaster. In addition, these studies will provide a model for how the potential for other innate behaviors are genetically specified in the nervous system during development.

Development of a respiratory neural circuit: Ontogeny of respiratory drive

Breathing is driven by the need to expel carbon dioxide (CO2), and CO2-sensitive neurons in the brainstem are critical to this drive. Identifying breathing-related, CO2-sensitive neurons in the central nervous system and characterizing their location, development, phenotype, function, and plasticity will be a major advance in basic understanding of breathing and its neural control. Dr Taylor's research will identify neurons and mechanisms that underlie CO2 sensitivity by investigating a developing neural circuit that controls breathing. Her research will elucidate development of CO2-induced respiratory drive in an organism whose transition from aquatic to terrestrial life may reflect evolutionary changes common to vertebrates, including humans. The frog is an ideal research model organism because its isolated brainstem provides, at any stage of development, the intact and functional brainstem circuit that controls breathing, and it allows long-term investigation of central respiratory CO2 responses under normal physiological conditions. No other vertebrate model offers this suite of advantages. Dr Taylor's research will transform current thinking about developmental change in central CO2 sensitivity, emphasizing that it is not a predetermined neurodevelopment but a dynamic, and potentially harnessable, neuroplasticity. This provocative line of research will characterize the development and plasticity of respiratory drive. The intellectual merit of this project is the identification of specific, multiple mechanisms of CO2 sensitivity in the brainstem. The project has broader impact in providing students at all academic levels the opportunity to participate actively in neuroscience research. Dr Taylor's home institution, the University of Alaska Fairbanks, and its Institute of Arctic Biology have a well-established culture of research-based teaching and experiential learning in life sciences. Already 6 high school, 21 undergraduate, and 5 graduate students have participated in this research - and this includes several Alaska Native and other diversity students.

An award is made to Oregon State University to purchase a confocal and two photon microscope system for life science research, education and training. Combined with the rapid increase in genomic information, confocal and two photon microscopy provides an unparalleled ability to identify the cellular components of living organisms, and to determine their functions. Key new features of this microscope include: two photon excitation for deep tissue imaging, and preservation of live organisms and cells; a tunable TiSa laser; 34 spectral detection channels; and high sensitivity GaAsP detectors for faster acquisition and dynamic imaging. Research and training programs of over 38 faculty in 12 departments and centers and 7 colleges will be strengthened and transformed by the novel capabilities of the new instrument. The research will advance knowledge of plants, animals, microbes, pathogens, symbionts and communities, in natural, managed, healthy and polluted environments, spanning agricultural, forest, ocean, and human ecosystems.

The novel capabilities of the two photon and confocal microscope, will advance solutions to the most complex challenges facing mankind including environmental health, ecosystem loss, sustainable food and energy production, infectious disease, and understanding behavior and the mind. A new undergraduate learning and research program on biological imaging will be enabled by the microscope acquisition and will provide students with the tools to understand and apply microscopy and imaging techniques, engage in inquiry-based research, conduct ethical and appropriate scientific methods. The interdepartmental Ph.D. program in Molecular and Cellular Biology program will be strengthened by the access provided students to cutting edge imaging technology. Access to this technology would benefit the broader Oregon research community, including small regional companies.

Through this S-STEM project the PI team at the University of Alaska Fairbanks is increasing the number of academically talented students with demonstrated financial need who earn baccalaureate degrees in environmental and natural sciences. The student cohort is comprised of 28 upper level undergraduates who are already at the university and transfer students from the five feeder community colleges as well as from Ilisagvik Tribal College. The goal of the project is to retain the scholarship students by integrating them into the Alaskan community of sustainability research and education. Project elements include (a) a comprehensive recruitment strategy, (b) a strong mentoring program, (c) career and communication workshops, and (d) supplementary courses and early research involvement. Acknowledging the regional need to prepare students who have backgrounds in environmental science and that participation in research related to solving civic problems has a strong appeal for Native American and Native Alaskan students, the project team has designed a rigorous, 30- credit hour curriculum for an interdisciplinary Certificate in Resilience and Adaptation (sustainability) which participants are encouraged to complete. In order to broaden participation, Native American and Native Alaskan students are recruited actively.

There are two important ways in which this project will have broad impact. First, data generated through assessment and evaluation is expected to support the rationale that high retention of students in STEM fields can be achieved through a comprehensive academic program linked to community-based research and civic engagement. Formative evaluation is carried out to examine whether or not a diverse group of students is recruited and equipped to (a) maintain the target GPA (3.0 or higher), (b) perform skills at the appropriate level, (c) graduate with a STEM degree. Summative evaluation is to ascertain whether or not the project goal to increase the number of well-prepared students in the selected fields is accomplished based on the Student Assessment of Learning Gains, student essays, and post-graduation data. Secondly, dissemination of the project results is expected to provide a model for implementation of community-based practices in recruitment and retention of STEM students. The project team plans to present their work at the national meetings on STEM teaching and learning as well as through the National Center for Science and Civic Engagement. Project deliverables include results of summative evaluation and the course materials developed for the Certificate in Resilience and Adaptation.