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Hemizygosity for the NF2 gene in humans causes a syndromic susceptibility to schwannoma development. However, Nf2 hemizygous mice do not develop schwannomas but mainly osteosarcomas. In the tumors of both species, the second Nf2 allele is inactivated. We report that conditional homozygous Nf2 knockout mice with Cre-mediated excision of Nf2 exon 2 in Schwann(More)
Although inappropriate activation of the Wnt/beta-catenin pathway has been implicated in the development of hepatocellular carcinoma (HCC), the role of this signaling in liver carcinogenesis remains unclear. To investigate this issue, we constructed a mutant mouse strain, Apc(lox/lox), in which exon 14 of the tumor-suppressor gene adenomatous polyposis coli(More)
BACKGROUND CARD15/NOD2 mutations are associated with susceptibility to Crohn's Disease (CD) and Graft Versus Host Disease (GVHD). CD and GVHD are suspected to be related with the dysfunction of Peyer's patches (PP) and isolated lymphoid follicles (LFs). Using a new mouse model invalidated for Card15/Nod2 (KO), we thus analysed the impact of the gene in(More)
Meningiomas are among the most common primary central nervous system tumours in adults. Studies focused on the molecular basis for meningioma development are hampered by a lack of information with regard to the cell of origin for these brain tumours. Herein, we identify a prostaglandin D synthase-positive meningeal precursor as the cell of origin for murine(More)
Kras is commonly mutated in colon cancers, but mutations in Nras are rare. We have used genetically engineered mice to determine whether and how these related oncogenes regulate homeostasis and tumorigenesis in the colon. Expression of K-Ras(G12D) in the colonic epithelium stimulated hyperproliferation in a Mek-dependent manner. N-Ras(G12D) did not alter(More)
The NF2 gene product, merlin/schwannomin, is a cytoskeleton organizer with unique growth-inhibiting activity in specific cell types. A narrow spectrum of tumors is associated with NF2 deficiency, mainly schwannomas and meningiomas, suggesting cell-specific mechanisms of growth control. We have investigated merlin function in mouse Schwann cells (SCs). We(More)
Loss of Apc appears to be one of the major events initiating colorectal cancer. However, the first events responsible for this initiation process are not well defined and the ways in which different epithelial cell types respond to Apc loss are unknown. We used a conditional gene-ablation approach in transgenic mice expressing tamoxifen-dependent Cre(More)
Cerebral cavernous malformations (CCM) are vascular malformations of the brain that lead to cerebral hemorrhages. In 20% of CCM patients, this results from an autosomal dominant condition caused by loss-of-function mutations in one of the three CCM genes. High expression levels of the CCM genes in the neuroepithelium indicate that CCM lesions might be(More)
Schwannomin/merlin is the product of a tumor suppressor gene mutated in neurofibromatosis type 2 (NF2). Although the consequences of NF2 mutations on Schwann cell proliferation are well established, the physiological role of schwannomin in differentiated cells is not known. To unravel this role, we studied peripheral nerves in mice overexpressing in Schwann(More)