Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Transcription profiling of mouse LckCre, CD4Cre-Ctnnbex3 mutants before and after T-cell transformation reveals stabilization of b-catenin induces lymphomas

ABSTRACT: Activation of b-catenin has been causatively linked to the etiology of colon cancer. Conditional stabilization of this molecule in pro-T-cells promotes thymocyte development without the requirement for preTCR signaling. We show here that activated b-catenin stalls the developmental transition from the double-positive (DP) to the single-positive (SP) thymocyte stage and predisposes DP thymocytes to transformation. b-Catenin induced thymic lymphomas have a leukemic arrest at the early DP stage. Lymphomagenesis requires Rag activity, which peaks at this developmental stage, as well as additional secondary genetic events. A consistent secondary event is the transcriptional upregulation of c-Myc, whose activity is required for transformation since its conditional ablation abrogates lymphomagenesis. In contrast, the expression of Notch receptors as well as targets is reduced in DP thymocytes with stabilized b-catenin and remains low in the lymphomas indicating that Notch activation is not required or selected for in b-catenin induced lymphomas. Thus, b-catenin activation may provide a mechanism for the induction of T-ALL that does not depend on Notch activation. Experiment Overall Design: This study was used to compare gene expression patterns of LckCre mice, CD4Cre-Ctnnbex3 mice before and after T-cell transformation. 5 independent Lckcre (control), 5 independent CD4Cre-Ctnnbex3 mice and 8 independent mice with lymphomas were used. Thymocytes or tumor masses were collected from Lckcre, CD4Cre-Ctnnbex3 mice. Total RNA isolation and purification followed by synthesis of dscDNA, Biotinylated cRNA and purification of Biotinylated cRNA. Then the hybridization to Affymetrix âMouse Expression Array 430 Genechipsâ was done. Data was analysed by dchip.

ORGANISM(S): Mus musculus

SUBMITTER: Fotini Gounari

PROVIDER: E-GEOD-7050 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Beta-catenin stabilization stalls the transition from double-positive to single-positive stage and predisposes thymocytes to malignant transformation.

Guo Zhuyan Z Dose Marei M Kovalovsky Damian D Chang Rui R O'Neil Jennifer J Look A Thomas AT von Boehmer Harald H Khazaie Khashayarsha K Gounari Fotini F

Blood 20070222 12

Activation of beta-catenin has been causatively linked to the etiology of colon cancer. Conditional stabilization of this molecule in pro-T cells promotes thymocyte development without the requirement for pre-TCR signaling. We show here that activated beta-catenin stalls the developmental transition from the double-positive (DP) to the single-positive (SP) thymocyte stage and predisposes DP thymocytes to transformation. beta-Catenin-induced thymic lymphomas have a leukemic arrest at the early DP ...[more]

PMID: 17317856

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Project description:Notch1 signaling is an important regulator of cell fate in early stages of T cell development. Because Notch receptors can function redundantly, we sought an approach for inhibiting all endogenous Notch signaling in thymocytes. Upon ligand engagement, Notch receptors undergo two successive proteolytic cleavages, the second involving a Presenilin (PS) containing complex with -secretase activity that releases a small intracellular fragment of Notch. This activated form of Notch (NotchIC) translocates from the membrane to the nucleus, where it acts as a transcription factor, inducing the expression of multiple target genes . Since Presenilins are required for the activation of all four mammalian forms of Notch, we generated mice with deletions of both Presenilin1 and Presenilin2 genes, the only genes encoding Presenilin in the mouse genome. To target Notch inactivation specifically to developing T cells, we introduced Cd4-Cre to mediate Presenilin gene deletion in a tissue- and stage-specific manner. Direct target genes of Notch signaling are largely unknown, and are likely to be cell lineage and stage specific. Therefore in order to identify potential Notch target genes , we compared RNA of thymocytes at the CD4+CD8+ stage of development from H-2b transgenic 5CC7 TCR/ RAG2-deficient / Presenilin1flox/flox /PS2-/- mice, with and without Cd4-Cre. Thymocyte single cell suspensions were generated using 100 µm nylon mesh (PGC Scientifics). DP thymocytes were isolated from RAG2° control or PS1/2° 5CC7 TCR H2bb mice by magnetic bead separation on anti-CD4 coated microbeads (Miltenyi Biotec.). Total RNA was isolated using TRIzol according to manufacturer's instructions (Invitrogen). After quantification and checking for integrity, 1 µg of RNA was subjected to linear amplification. The resulting aRNA was labeled by reverse transcription via Cy5-dCTP incorporation and Cy3-dCTP incorporation. The fluorescent labeled probes were subsequently combined and hybridized on topic-defined PIQORTM Immunology Microarrays Mouse Antisense.

Dataset Information

Transcription profiling of mouse LckCre, CD4Cre-Ctnnbex3 mutants before and after T-cell transformation reveals stabilization of b-catenin induces lymphomas

Publications

Beta-catenin stabilization stalls the transition from double-positive to single-positive stage and predisposes thymocytes to malignant transformation.

Similar Datasets

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