Project description:Previously, transcriptomics data for mollusc has been obtained by whole-brain bulk RNA-seq and low-throughput scRNA-seq. We want to construct the first molluscan high-throughput single-neuron transcriptomes for Berghia stephanieae. Around 129,000 cells were collected from 20 brains and the libraries were constructed using the 10X Genomics' Chromium platform. The brains were separated into two samples: the main brain (i.e., the cerebropleural, pedal, buccal ganglion) and the rhinophore ganglion sample. After library preparation, around 1,000 cells were receovered and sequenced. After data analysis, the cells formed eight clusters with marker genes for each cluster identified. Various cell populations that express a wide range of both small-molecule neurotransmitters and neuropeptides such as serotonergic, small cardioactive peptide (SCP), APGWamide, and FMRFamide cells were also identified in the dataset. Interestingly, cells from the rhinophore ganglion of Berghia exhibit great cell heterogeneity, with cells splitting into two general categories and four distinct clusters. The project produced a single-cell dissociation protocol that can be adapted for use in other nudibranch molluscs and a custom data analysis pipeline for data of this nature.
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.
Project description:A novel protein, soritesidine (SOR) with potent toxicity was isolated from the marine sponge Spongosorites sp. SOR exhibited wide range of toxicities over various organisms and cells including brine shrimp (Artemia salina) larvae, sea hare (Aplysia kurodai) eggs, mice, and cultured mammalian cells. Toxicities of SOR were extraordinary potent. It killed mice at 5 ng/mouse after intracerebroventricular (i.c.v.) injection, and brine shrimp and at 0.34 µg/mL. Cytotoxicity for cultured mammalian cancer cell lines against HeLa and L1210 cells were determined to be 0.062 and 12.11 ng/mL, respectively. The SOR-containing fraction cleaved plasmid DNA in a metal ion dependent manner showing genotoxicity of SOR. Purified SOR exhibited molecular weight of 108.7 kDa in MALDI-TOF MS data and isoelectric point of approximately 4.5. N-terminal amino acid sequence up to the 25th residue was determined by Edman degradation. Internal amino acid sequences for fifteen peptides isolated from the enzyme digest of SOR were also determined. None of those amino acid sequences showed similarity to existing proteins, suggesting that SOR is a new proteinous toxin.