Intellectual merit: Cytokinesis is achieved by the formation of a cleavage furrow in anaphase that bisects the mitotic spindle between the separated chromosomes, cytoplasm and organelles. The goal of this research activity is to gain insight into the mechanisms required to establish cleavage furrows, identify factors required to regulate furrow formation and to determine how DIP-1, a novel dynamin/DYN-1 interacting protein, coordinates this process. The underlying hypothesis is that the cleavage furrow is established by clustering of lipid raft proteins by an unknown signal(s) from the spindle. This signal triggers DIP-1 to regulate the targeting and assembly of dynamin/DYN-1, a known raft component, at the equatorial membrane of the cell during the metaphase-anaphase transition. Dynamin/DYN-1 subsequently directs actin filament formation, which assemble into the acto-myosin ring and in turn, promotes cleavage furrow invagination and completion. This hypothesis is based on the observations that: 1) The target of the signal for cytokinesis is the equatorial cortex; 2) DYN-1 localizes to equatorial membranes and newly formed cleavage furrows; 3) Dynamin is a known lipid raft component; 4) Dynamin can influence actin assembly; and 5) DIP-1, like DYN-1, regulates the establishment of cleavage furrow formation as well as completion. Based on these observations, the experimental focus of this project is on the role of DIP-1 in establishing the cleavage furrow and regulating DYN-1 function during cytokinesis in animal cells, using the nematode, C. elegans, as a model. Preliminary studies in dip-1 (RNAi) embryos show that (i) the spindle midzone microtubules assemble properly, but buckle and disappear during late anaphase (60%); (ii) the formation of cytoplasmic, spherical tubulin::GFP aggregates are observed (40%); (iii) the actin cortex is disorganized and membrane ruffling during cytokinesis is almost absent; and (iv) DIP-1 contains a BRCT motif commonly used to mediate interactions with other BRCT motif-containing proteins, such as BRCA2 and ECT2, known cytokinesis proteins. The strategy of this study is to: 1) Determine the cellular function of DIP-1; 2) Characterize the membrane-cytoskeletal consequences of DIP-1 depletion during cytokinesis; 3) Determine if DIP-1 directly binds to DYN-1; and 3) Determine the cell cycle localization of DIP-1::GFP and identify protein motifs and additional factors that regulate DIP-1::GFP localization during mitosis. These studies should provide new insight into the regulation and function of the membrane-cytoskeletal events that occur during cytokinesis with an understanding of the specific role of DIP-1 in this process.
Broader Impact: This CAREER project also involves a significant, integrated educational component, designed to benefit both the students involved directly with the work and for the public, especially for local Native American communities. The high school, undergraduate and graduate students involved in or introduced to this research will gain hands-on experience using in vivo microscopy techniques in conjunction with genetics, biochemistry and molecular biology. Since live movies of cell division in C. elegans embryos are quite exciting and easy to comprehend, Dr. Skop's work is especially welcoming to all educational backgrounds. Since "systems biology" will be taught and performed in the laboratory, the introduction to these techniques will be skills that are highly sought after in the fields of genomics, proteomics and biology. Information about Dr. Skop's work and her "systems biology" course (Genetics 875) will be disseminated to the academic and high school communities through online resources related to her laboratory and courses.
Intellectual Merit: My research program examines the mechanisms that regulate cell division. The work in my lab integrates several approaches from genetics, cell biology, genomics and proteomics accompanied with high resolution in vivo microscopy to accomplish these goals. With the support of the NSF CAREER award, my research group examined the role of a gene called, rack-1 in the events that occur during cell division in the early worm embryo. Our findings suggest that membrane trafficking is tightly coordinated and maintained throughout the cell cycle to ensure proper cell asymmetry and division during embryonic development. Broader Impacts: With support from the NSF, I have improved minority recruitment efforts and enrollment on the UW-Madison campus. I have been deeply involved in several minority outreach programs on campus and in the Madison community. These programs range from visits by middle school students to my lab to lectures about my love for science and art to general public. I have also continued to promote science at all levels through the organization of scientific art shows on the local and international levels. I am dedicated to making science accessible to every race and group and the general public. Minority Outreach and Recruitment My lab has extensive experience with outreach to minority groups at the local and national levels. As being part Native American (Cherokee), I serve as a unique role model for the Native American student population, especially in the sciences. Since I joined the faculty in Madison, the Native American applicants and enrollment for doctoral candidates in our department alone has nearly tripled. Through my involvement in SACNAS, AISES, New Mexico State University visits and REU/SROP programs, I have directly contributed to this positive trend in minority graduate student enrollment on the UW-Madison campus. TINY: Art form Microscopes at UW-Madison Scientific art shows are a great way to make science accessible by the general public. In collaboration with Tandem Press and campus researchers, I organized a scientific art show at the Dane County/Madison airport. This show is called, "TINY: Art from microscopes at UW-Madison" and is now touring the country. About 40 beautifully framed images feature cells, molecules and nanoscale structures generated by campus researchers over the last 10 years. The magnified images include trichomes on plant leaves, zebra fish embryos, butterfly and plant cells and carbon nanotubes. The show has been a huge success so far and has even been written up in the USA Today, NPR online and Chicago Tribune. The show is currently traveling the country and has been in several university libraries and museums. International C. elegans Art Show For the past 14 years, I have organized the International C. elegans Art Show. I have raised prize money and microscope supplies for winners, along with prize money provided by the Genetics Society of America. It is now considered a "highlight" of the meeting. I have found that a large percentage (~45%) of art show first prize winners have gone on to become academic faculty (if they weren’t already), attesting the importance of creativity in science. Several of the winning images are also placed in the C. elegans Gift Shop (www.cafepress.com/celegans), of which I curate.
