Project description:Fungal endophytes often live in symbiotic relationships with various plant hosts, conferring positive effects to their host organism. These endophytes frequently produce a wide variety of secondary metabolites with bioactivities that are often responsible for the beneficial effects seen in the host, such as antifungal or anti-insectan activity. A large group of fungal endophytes isolated from Canadian fruit crops including blueberries, raspberries, cranberries, grapes, and pears, was analyzed using molecular networking by GNPS in an effort to simplify the process of examining a large dataset. Molecular networking increased the speed and efficiency of examining this dataset, permitting the dereplication of 60 known compounds and the discovery of seven putative novel compounds, which will be purified, characterized, and tested for bioactivity in future studies.
Project description:The intermediate filament protein Nestin serves as a biomarker for stem cells and has been used to identify subsets of cancer stem-like cells. However, the mechanistic contributions of Nestin to cancer pathogenesis are not understood. Here we report that Nestin binds the hedgehog pathway transcription factor Gli3 to mediate the development of medulloblastomas of the hedgehog subtype. In a mouse model system, Nestin levels increased progressively during medulloblastoma formation resulting in enhanced tumor growth. Conversely, loss of Nestin dramatically inhibited proliferation and promoted differentiation. Mechanistic investigations revealed that the tumor-promoting effects of Nestin were mediated by binding to Gli3, a zinc finger transcription factor that negatively regulates hedgehog signaling. Nestin binding to Gli3 blocked Gli3 phosphorylation and its subsequent proteolytic processing, thereby abrogating its ability to negatively regulate the hedgehog pathway. Our findings show how Nestin drives hedgehog pathway-driven cancers and uncover in Gli3 a therapeutic target to treat these malignancies. Nestin+ and Nestin- GNPs (granule neuron precursors) were purified from Nestin-CFP/Math1-Cre/Ptch1-loxp cerebella at postnatal day 4 by FACs, and total RNA from these two cell populations were extracted, and then labeled and hybridized to Affymetrix Mouse Genome 430 2.0 arrays.