Project description:We previously identified rearrangements involving CIITA, the master transcriptional regulator of MHC class II expression, as common mutational events in PMBCL and cHL. In order to inform on the prevalence and different types of structural genomic aberrations affecting CIITA in PMBCL and HL we performed high-resolution copy number analysis. Affymetrix SNP6 arrays were performed according to the manufacturer's instructions on DNA extracted from cell lines.
Project description:AIMAH is an ACTH-independent bilateral enlargement of the adrenal cortex occuring during adulthood. The enlargment is related to the growth of multiple benign nodules. This condition is associated with various degrees of cortisol hypersecretion. The occurence of several nodules in both adrenals, and the existence of familial forms, suggest the existence of a germline genetic predisposition. To find the gene(s), the aim of the project was to look for recurrent chromosomal alterations in the AIMAH nodules. Extensive mapping of somatic gains, losses and copy-neutral loss of heterozygosity (LOH) was performed with Affymetrix SNP6 arrays. A copy neutral LOH of 16p, occuring in 7 of 26 patients, was one of the only recurrent alterations, pointing towards a candidate gene in this region. Of note this condition differs from the congenital adrenal hyperplasias, related to genetic alterations of steroidogenesis (the latter is an ACTH dependent adrenal hyperplasia). Affymetrix SNP6 arrays were performed according to the manufacturer's directions on DNA extracted from cryopreserved tumor samples or peripheral blood samples.
Project description:SNP6 profiling of papillary carcinoma of the breast Affymetrix SNP6 arrays were performed according ro manufacturer's directions on DNA extracted from 16 papillary carcinomas of the breast.
Project description:Mutations in the ATRX chromatin remodeller predispose to a developmental genetic disorder and cancer, but how ATRX safeguards genome and telomere stability remains unresolved. Here, we uncover critical dependencies for the CTC1-STN1-TEN1 (CST) complex and RAD9A-HUS1-RAD1 (9-1-1) clamp in ATRX deficient cells. ATRX:CST synthetic lethality manifests following accumulation of telomeric G-rich ssDNA, which results in telomere loss and cell death. Conversely, we attribute ATRX:9-1-1 synthetic lethality to genome-wide ssDNA lesions, which compromise DNA replication. We further show that ATRX suppresses DNA damage during replication stress by counteracting the activity of the FAM111A protease. We demonstrate that roles of ATRX in telomere maintenance and replication are genetically separable, requiring its ATPase activity and PIP-box, respectively. We also show that such roles protecting genome stability are largely independent of the ATRX-DAXX interaction. Collectively, our data show that functions of ATRX in suppressing toxic ssDNA lesions are context-dependent and are key to global DNA replication and telomere integrity.
Project description:The chromatin regulator ATRX is inactivated in large subsets of adult and pediatric glioma. Whether and how ATRX deficiency promotes oncogenesis by epigenomic dysregulation remains unclear. We found that Atrx loss, especially when coupled with Tp53 inactivation, promoted cell motility and modulated differentiation state in primary murine neuroepithelial progenitors, recapitulating characteristic disease phenotypes and molecular features. Moreover, Atrx deficiency induced widespread shifts in chromatin accessibility, histone composition, and gene transcription at vacant Atrx binding sites distributed across the genome. Finally, target genes mediating Atrx-deficient phenotypes in vitro exhibited similarly selective misexpression in ATRX-mutant human glioma tissues and cell lines. These findings demonstrate that, in appropriate physiological contexts, ATRX deficiency and its epigenomic sequelae are sufficient to induce disease-defining oncogenic phenotypes.
Project description:The histone variant macroH2A generally associates with transcriptionally inert chromatin, however the factors that regulate its chromatin incorporation remain elusive. Here, we identify the SWI/SNF helicase, ATRX, as a novel macroH2A interacting protein. Unlike its role in assisting H3.3 chromatin deposition, ATRX acts as a negative regulator of macroH2A’s chromatin association. In human erythroleukemic cells deficient for ATRX, ChIP-sequencing studies reveal that macroH2A accumulates at the HBA gene cluster on the subtelomere of chromosome 16, coinciding with the loss of α globin expression. Collectively, our results implicate deregulation of macroH2A’s distribution as a contributing factor to the α thalassemia phenotype of ATRX syndrome. Mononucleosomes from K562 cells bearing integrated lentiviral shRNA constructs targeting either luciferase (shluc) or ATRX (sh92) were isolated and ChIP'd with mH2A1 antibody. DNA from shluc Input and the two mH2A1 ChIPs were isolated and sequenced on Illumina's Hiseq.