Project description:Genes specific to Sox9+ pancreatic progenitors were identified by comparing the gene expression in embryonic and adult Sox9+ cells. We used microarray analysis to detail the global changes in gene expression as Sox9 positive embryonic pancreatic progenitors differentiatiate into adult ductal cells or the endocrine lineage. GFP positive cells from Sox9-EGFP mouse pancreas were isolated by FACS at different stages of development (e10.5, e15.5, and p23) for RNA extraction and hybridization to Affymetrix microarrays. To obtain populations highly enriched in Sox9 expression, we collected only GFP Hi populations for analysis. To identify gene expression changes specific to the differentiation of progenitors to ductal cells or endocrine cells, we also isolated and analyzed the gene expression profile of GFP negative cells isolated at p23, as well as GFP positive cells isolated from Ngn3-EGFP mouse pancreas at e15.5. These two populations allow the identification of genes whose expression is associated with the newly differentiated endocrine progeny in the embryo (Ngn3-GFP positive) and adult acinar and endocrine cells at p23.
Project description:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other
Project description:This experiment was designed to analyze the expression of genes in dorsal pancreatic cells at two temporally separated stages of pancreas development. This was accomplished by comparing expression profiles of embryonic dorsal pancreas tissue from Ngn3 null mice with wild-type littermates at days 13 and 15 of embryonic development. The comparison of gene expression in mutant and wild-type pancreas was used primarily to show genes that are lower expressed/missing in the mutant, as Ngn3 null mice have no endocrine pancreas tissue. From each developmental stage, five wild-type and five mutant samples were chosen, representing embryos from at least three different litters. Wild-type and mutant samples from the common stage of development were paired randomly and analysed in flipped colour. Probes were spotted in duplicate on each slide in a randomised (fixed) layout, effectively distributing the duplicate spots randomly over the slide.
Project description:The basic helix-loop-helix transcription factor Neurogenin3 (Ngn3/Neurog3) is expressed in endocrine progenitor cells in the embryonic mouse pancreas. Ngn3 controls endocrine cell fate decisions. Ngn3 deficient mice do not develop any pancreatic endocrine cells, including insulin producing beta cells, and die postnatally from diabetes. Therefore, the characterization of gene expression in Ngn3-expressing cells and their progeny is of particular interest for the development of novel strategies for cell replacement therapies in type-1 diabetes. Here we describe two studies. In the first study (8 assays) we used mice where the EYFP (Enhanced Yellow fluorescent Protein) is expressed under the control of Ngn3 regulatory elements (knock add on strategy). EYFP-positive, Ngn3-expressing cells, were FACS sorted from embryonic pancreas at day 15.5 (E15.5), as well as EYFP-negative cells. In the second study (6 assays) we compared wild-type and Ngn3 mutant pancreas at E15.5. All samples were hybridized to Affymetrix GeneChip Mouse Genome 430.2.0 array.
Project description:We found that BAP1 (BRCA1 Associated Protein-1) shows loss of heterozygosity in over 25% of pancreatic cancer patients and functions as tumor suppressor. Conditional deletion of Bap1 in murine pancreas led to genomic instability, accumulation of DNA damage, and an inflammatory response that evolved to pancreatitis with full penetrance. Concomitant expression of oncogenic KrasG12D led to malignant transformation and development of invasive and metastatic pancreatic cancer. At the molecular level, BAP1 maintains the integrity of the exocrine pancreas by regulating genomic stability and its loss confers sensitivity to radio- and platinum-based therapies.
Project description:Pancreatic endocrine cells arise from a NGN3+ population during pancreas organogenesis. To gain a more thorough understanding of this progenitor pool, we used a reporter mouse - NGN3-EGFP - and sorted EGFP+ cells from e15.5 pancreata of control animals. The data generated from this experiment will allow us to visualize gene expression levels in endocrine progenitors during normal development and can be used to compare against mutant animal gene expression.
Project description:NGN3 is a transcription factor whose transient expression during pancreatic development is vital for the generation of endocrine pancreatic cells, including beta cells. NGN3 stabilisation has been shown to induce exocrine-to-endocrine cell plasticity in the murine pancreas, making it a viable target for therapies aiming to replenish beta cells after immune-mediated destruction in type 1 diabetes patients. Here, we set out to identify new interactors of NGN3 that could play a role in its post-translational regulation. We transfected HEK293A cells with HA-tagged NGN3 and carried out immunoprecipitation of the HA-tag, followed by analysis of co-immunoprecipitated interactors via LC-MS/MS.