Project description:Comparison of gene expression in intestinal epithelial cells in the presence or absence of ectopic induction of MSI2 in vivo Total RNA was isolated from preparations of total intestinal epithelial cells taken from the jejunum from 3 control (R26-M2rtTA +doxycycline for 24 hrs) and 3 experimental (TRE-MSI2::R26-M2rtTA +doxycycline for 24 hrs) and subjected to profiling on affymetrix Gene 1.0ST arrays
Project description:The MSI2 RNA binding protein has recently emerged as a potent oncogene playing key roles in hematopoietic stem cell homeostasis and malignant hematopoiesis. Here we demonstrate that MSI2 is expressed in the intestinal stem cell compartment, that its expression is elevated in colorectal adenocarcinomas, and that MSI2 loss of function abrogates colorectal cancer cell growth. We thus examined the oncogenic consequences of MSI2 gain of function in the intestinal epithelium with a drug inducible mouse model. Strikingly, MSI2 induction alone was sufficient to phenocopy the majority of morphological and molecular consequences of acute loss of the APC tumor suppressor in the intestinal epithelium. We demonstrate that this phenotype is independent of both the activation of the other oncogenic Musashi family member, Msi1, and of canonical Wnt pathway activation. Transcriptome-wide RNA-binding analysis indicates that MSI2 acts as a pleiotropic inhibitor of known intestinal tumor suppressors including Lrig1, Bmpr1a, Cdkn1a, and Pten. Finally, we demonstrate that inhibition of the PDK-AKT-mTORC1 axis downstream of Pten rescues oncogenic consequences of MSI2 induction. Taken together, our findings identify MSI2 as a central component in an unappreciated oncogenic pathway promoting intestinal transformation. 2 wild-type samples, 2 TRE-Msi2 samples
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:Comparison of gene expression in intestinal epithelial cells in the presence or absence of ectopic induction of Msi1 in vivo Total RNA was isolated from preparations of total intestinal epithelial cells taken from the jejunum from 3 control (R26-M2rtTA +doxycycline for 24 hrs) and 3 experimental (TRE-Msi1::R26-M2rtTA +doxycycline for 24 hrs) animals and subjected to profiling on affymetrix Gene 1.0ST arrays