Project description:Chromoanagenesis is a descriptive term that encompasses classes of catastrophic mutagenic processes that generate localized and complex chromosome rearrangements in both somatic and germline genomes. Herein we describe a 5-year-old female presenting with a constellation of clinical features consistent with a clinical diagnosis of Coffin-Siris syndrome 1 (CSS1). Initial G-banded karyotyping detected a 90 Mb pericentric and 47 Mb paracentric inversion on a single chromosome. Subsequent analysis using short-read whole genome sequencing, and genomic optical mapping revealed additional inversions, all clustered on chromosome 6, one of them disrupting ARID1B for which haploinsufficiency leading to CSS1. In all, the resolved derivative chromosome architecture presents four de novo inversions, one pericentric and three paracentric, involving six breakpoint junctions in what appears to be a shuffling of genomic material on this chromosome. Each junction was resolved to nucleotide-level resolution with mutational signatures suggestive of non-homologous end joining. The disruption of the gene ARID1B is shown to occur between the 4th and 5th exon of the canonical transcript with subsequent qPCR studies confirming a decrease in ARID1B expression in the patient versus healthy controls. Deciphering the underlying genomic architecture of chromosomal rearrangements and complex structural variants may require multiple technologies and can be critical to elucidating the molecular etiology of a patient’s clinical phenotype or resolving unsolved Mendelian disease cases.
Project description:The goal of this experiment was to determine the size, genomic extent and gene content of complex rearrangements involving chromosome 9q
Project description:The goal of this experiment was to determine the size, genomic extent and gene content of complex rearrangements involving multiple chromosomes
Project description:Chromothripsis represents a novel phenomenon in the structural variation landscape of cancer genomes. Here, we analyzed the genomes of ten patients with congenital disease that were preselected to carry complex chromosomal rearrangements (CCRs) with more than two breakpoints. The rearrangements displayed unanticipated complexity resembling chromothripsis. We find that eight of them contain hallmarks of multiple clustered double-stranded DNA breaks (DSBs) on one or more chromosomes. In addition, nucleotide resolution analysis of 98 breakpoint-junctions indicates that break-repair involves non-homologous or microhomology mediated end-joining. We observed that these eight rearrangements are balanced or contain sporadic deletions ranging in size between a few hundred bp and several Mb. The two remaining complex rearrangements did not display signs of DSBs and contain duplications, indicative of rearrangement processes involving template-switching. Our work provides detailed insight in the characteristics of chromothripsis and supports a role for clustered DSBs driving some constitutional chromothripsis rearrangements. We analyzed five patient-parent trios with Illumina BeadChip arrays to test for (de novo) copy number variants and to analyze the parental origin of the complex rearrangements in these patients.
Project description:Chromothripsis represents a novel phenomenon in the structural variation landscape of cancer genomes. Here, we analyzed the genomes of ten patients with congenital disease that were preselected to carry complex chromosomal rearrangements (CCRs) with more than two breakpoints. The rearrangements displayed unanticipated complexity resembling chromothripsis. We find that eight of them contain hallmarks of multiple clustered double-stranded DNA breaks (DSBs) on one or more chromosomes. In addition, nucleotide resolution analysis of 98 breakpoint-junctions indicates that break-repair involves non-homologous or microhomology mediated end-joining. We observed that these eight rearrangements are balanced or contain sporadic deletions ranging in size between a few hundred bp and several Mb. The two remaining complex rearrangements did not display signs of DSBs and contain duplications, indicative of rearrangement processes involving template-switching. Our work provides detailed insight in the characteristics of chromothripsis and supports a role for clustered DSBs driving some constitutional chromothripsis rearrangements.
Project description:The integration of T-DNA to plant genomes is widely used for basic research and agriculture. High heterogeneity in the number of integration events per genome, their configuration and impact on genome integrity highlight both, the critical need and great challenge to detect the genomic locations of T-DNA insertions and their associated chromosomal rearrangements. Here we present ‘4SEE’, a circular chromosome conformation capture (4C) based method for robust, rapid and cost-efficient detection of the entire scope T-DNA locations. Moreover, by measuring the chromosomal architecture at plant genome flanking the T-DNA insertions, 4SEE outlines their associated complex chromosomal aberrations. Applying 4SEE to a collection of confirmed T-DNA lines revealed previously unmapped T-DNA insertions and chromosomal rearrangements such as inversions and translocations. Uncovering such events in feasible, robust and cost-effective manners by 4SEE in any plant of interest have implications for accurate annotation and phenotypic characterization of T-DNA insertion mutants and transgene expression in basic science applications as well as for plant biotechnology.
Project description:The genetics of classical Hodgkin lymphoma (cHL) is poorly understood. The finding of a JAK2-involving t(4;9)(q21;p24) in one case of cHL prompted us to characterize this translocation on a molecular level and to determine the prevalence of JAK2 rearrangements in cHL. We showed that the t(4;9)(q21;p24) leads to a novel SEC31A-JAK2 fusion. Screening of 131 cHL cases identified one additional case with SEC31A-JAK2 and two additional cases with rearrangements involving JAK2. We demonstrated that SEC31A-JAK2 is oncogenic in vitro and acts as a constitutively activated tyrosine kinase that is sensitive to JAK inhibitors. In vivo, SEC31A-JAK2 was found to induce a T-lymphoblastic lymphoma or myeloid hyperplasia in a murine bone marrow transplant model. Altogether, we identified SEC31A-JAK2 as a first aberration characteristic for cHL and provide evidence that JAK2 rearrangements occur in a minority of cHL cases. Given the proven oncogenic potential of this novel fusion, our studies provide new insights into the pathogenesis of cHL and indicate that in at least some cases, constitutive activation of the JAK-STAT pathway is caused by JAK2 rearrangements. The finding that SEC31A-JAK2 responds to JAK inhibitors indicates that patients with cHL and JAK2 rearrangements may benefit from targeted therapies. Genomic profiling of primary and secondary transplanted mice expressing SEC31A-JAK2 with myeloid hyperplasia and T-lymphoblastic lymphoma Individual sample against a normal control