Complex Genomic Rearrangements at the PLP1 Locus Include Triplication and Quadruplication
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE63594 | GEO | 2014/11/25
SECONDARY ACCESSION(S): PRJNA268363
REPOSITORIES: GEO
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Project description:Inverted repeats (IRs) can facilitate structural variation as crucibles of genomic rearrangement. Complex DUP-TRP/INV-DUP rearrangements that contain breakpoint junctions within IRs have been recently associated with both MECP2 duplication syndrome (MIM#300260) and Pelizaeus-Merzbacher disease (PMD, MIM#312080). We investigated 17 unrelated PMD subjects with copy number gains at the PLP1 locus including triplication and quadruplication of specific genomic intervals M-bM-^@M-^S 16/17 were found to have a DUP-TRP/INV-DUP rearrangement product. An IR distal to PLP1 facilitates DUP-TRP/INV-DUP formation as well as an inversion structural variation found frequently amongst normal individuals. We show that a homologyM-bM-^@M-^Tor homeologyM-bM-^@M-^Tdriven replicative mechanism of DNA repair can apparently mediate template switches within stretches of microhomology. Moreover, we provide evidence that quadruplication, and potentially higher order amplification of a genomic interval, can occur in a manner consistent with rolling circle amplification as predicted by the microhomology mediated break induced replication (MMBIR) model. To determine size, genomic extent and gene content for each rearrangement, we used a customized tiling-path oligonucleotide microarray spanning the Xq22 chromosomal region to query the genomic DNA of 7 males with Pelizaeus-Merzbacher disease, and 5 unaffected or carrier/unaffected family members. A 4x44k Agilent Technologies (Santa Clara, CA) microarray was designed using the Agilent e-array website targeting the region of the genome encompassing the dosage-sensitive PLP1 gene.
2014-11-25 | E-GEOD-63594 | biostudies-arrayexpress
Project description:The duplication-triplication/inverted-duplication (DUP-TRP/INV-DUP) structure is a type of complex genomic rearrangement (CGR). Although it has been identified as an important mutation signature of pathogenicity for genomic disorders and cancer genomes, its architecture remains unresolved. Here we studied the genomic architecture of DUP-TRP/INV-DUP by investigating the DNA of 24 patients identified by array comparative genomic hybridization (aCGH) on whom we found evidence for the existence of 4 out of 4 predicted structural variant (SV) haplotypes. Using a combination of short-read genome sequencing (GS), long-read GS, optical genome mapping and StrandSeq the haplotype structure was resolved in 18 samples. The point of template switching in 4 samples was shown to be a segment of ~2.2-5.5 kb of 100% nucleotide similarity. These data provide experimental evidence supporting the hypothesis that inverted LCRs act as a recombinant substrate. This type of CGR can result in multiple conformers which contributes to generate diverse SV haplotypes in susceptible loci.
2023-12-18 | GSE250451 | GEO
Project description:We investigated the features of the genomic rearrangements in a cohort of 50 male individuals with proteolipid protein 1 (PLP1) copy number gain events who were ascertained with Pelizaeus-Merzbacher disease (PMD; MIM: 312080). Genomic rearrangements in PMD individuals with PLP1 copy number gain events were investigated by high-density customized array and breakpoint junction sequence analysis. Analysis of these data enabled the spectrum and relative distribution of the underlying genomic mutational signatures to be delineated. Genomic rearrangements in PMD individuals with PLP1 copy number gain events were investigated by high-density customized array and breakpoint junction sequence analysis.
2019-10-09 | GSE138542 | GEO
Project description:Pelizaeus-Merzbacher disease (PMD) is a severe hypomyelinating disease, characterized by ataxia, intellectual disability, epilepsy and premature death. In the majority of cases, PMD is caused by duplication of PLP1 that is expressed in myelinating oligodendrocytes. Despite detailed knowledge of PLP1, there is presently no curative therapy for PMD. We used a Plp1 transgenic PMD mouse model to test the therapeutic effect of Lonaprisan, an antagonist of the nuclear progesterone receptor, in lowering Plp1 mRNA overexpression. We applied placebo-controlled Lonaprisan therapy to PMD mice for 10 weeks and performed the grid slip analysis to assess the clinical phenotype. Additionally, mRNA expression and protein accumulation as well as histological analysis of the central nervous system were performed. While Plp1 mRNA levels are increased about 1.8-fold in PMD mice compared to wildtype controls, daily Lonaprisan treatment reduced overexpression at the RNA level up to 1.5-fold, which was sufficient to significantly improve a poor motor phenotype. Electron microscopy confirmed a 25% increase in the number of myelinated axons in the corticospinal tract when compared to untreated PMD mice. Microarray analysis revealed the upregulation of pro-apoptotic genes in PMD mice that could be partially rescued by Lonaprisan treatment, which also reduced microgliosis, astrogliosis, and lymphocyte infiltration. We treated mice with Lonaprisan or vehicle for 10 weeks. Brains from 13 week old mice were collected and subsequently lysed for total RNA extraction. We took three biological replicates for each Treatment and Placebo.
2014-02-26 | E-GEOD-55315 | biostudies-arrayexpress
Project description:Pelizaeus-Merzbacher disease (PMD) is a severe hypomyelinating disease, characterized by ataxia, intellectual disability, epilepsy and premature death. In the majority of cases, PMD is caused by duplication of PLP1 that is expressed in myelinating oligodendrocytes. Despite detailed knowledge of PLP1, there is presently no curative therapy for PMD. We used a Plp1 transgenic PMD mouse model to test the therapeutic effect of Lonaprisan, an antagonist of the nuclear progesterone receptor, in lowering Plp1 mRNA overexpression. We applied placebo-controlled Lonaprisan therapy to PMD mice for 10 weeks and performed the grid slip analysis to assess the clinical phenotype. Additionally, mRNA expression and protein accumulation as well as histological analysis of the central nervous system were performed. While Plp1 mRNA levels are increased about 1.8-fold in PMD mice compared to wildtype controls, daily Lonaprisan treatment reduced overexpression at the RNA level up to 1.5-fold, which was sufficient to significantly improve a poor motor phenotype. Electron microscopy confirmed a 25% increase in the number of myelinated axons in the corticospinal tract when compared to untreated PMD mice. Microarray analysis revealed the upregulation of pro-apoptotic genes in PMD mice that could be partially rescued by Lonaprisan treatment, which also reduced microgliosis, astrogliosis, and lymphocyte infiltration.
2014-02-26 | GSE55315 | GEO
Project description:Pelizaeus-Merzbacher disease (PMD) is a pediatric disease of myelin in the central nervous system and manifests with a wide spectrum of clinical severities. Although PMD is a rare monogenic disease, hundreds of mutations in the X-linked myelin gene proteolipid protein 1 (PLP1) have been identified in humans. Attempts to identify a common pathogenic process underlying PMD have been complicated by an incomplete understanding of PLP1 dysfunction and limited access to primary human oligodendrocytes. To address this, we generated panels of human induced pluripotent stem cells (hiPSCs) and hiPSC-derived oligodendrocytes from 12 individuals with mutations spanning the genetic and clinical diversity of PMD—including point mutations and duplication, triplication, and deletion of PLP1—and developed an in vitro platform for molecular and cellular characterization of all 12 mutations simultaneously. We identified individual and shared defects in PLP1 mRNA expression and splicing, oligodendrocyte progenitor development, and oligodendrocyte morphology and capacity for myelination. These observations enabled classification of PMD subgroups by cell-intrinsic phenotypes and identified a subset of mutations for targeted testing of small-molecule modulators of the endoplasmic reticulum stress response, which improved both morphologic and myelination defects. Collectively, these data provide insights into the pathogeneses of a variety of PLP1 mutations and suggest that disparate etiologies of PMD could require specific treatment approaches for subsets of individuals. More broadly, this study demonstrates the versatility of a hiPSC-based panel spanning the mutational heterogeneity within a single disease and establishes a widely applicable platform for genotype-phenotype correlation and drug screening in any human myelin disorder.
2017-04-04 | GSE96049 | GEO
Project description:Angelman syndrome (AS) and interstitial duplication 15q autism (int dup(15)) are reciprocal genomic disorders caused by maternal deletion or duplication of the 15q11.2-q13 region. While AS is caused by maternal loss of 15q and maternal duplications of 15q can cause autism implicating the maternally expressed UBE3A gene in these phenotypes. We investigated chromatin and gene expression changes in blood and cell lines from three int dup(15) and three reciprocal AS deletion subjects to identify global genomic and gene expression changes that may influence both the AS and autism phenotypes. Using formaldehyde-assisted isolation of regulatory elements (FAIRE) we identified 1104 regions of differential open chromatin in AS deletion and 2344 regions int dup(15) indicating changes in chromatin could influence gene expression in these regions. Microarray analysis revealed 1225 genes that were elevated in AS deletion vs int dup(15) and 976 genes that were elevated in int dup(15) vs AS deletion PBMC (pvalue<0.05). Significant differences in expression were found for genes at the 15q locus like UBE3A, ATP10A and HERC2. A larger set of genes involved in chromatin remodeling, DNA repair and neurogenesis were found, at FAIRE peaks in AS deletion samples but had increased transcription in int dup(15) samples. There was a significant enhancement for genes with FOXP1 binding sites in the int dup(15) gene set and elevated FOXP1 protein could be detected in the nucleus of int dup(15) as compared to AS deletion cell lines. This analysis provides the first insights into transcriptional changes which may unveil new sets of genes and pathways contributing to both AS and autism pathogenesis.
2014-10-09 | GSE32563 | GEO
Project description:Angelman syndrome (AS) and interstitial duplication 15q autism (int dup(15)) are reciprocal genomic disorders caused by maternal deletion or duplication of the 15q11.2-q13 region. While AS is caused by maternal loss of 15q and maternal duplications of 15q can cause autism implicating the maternally expressed UBE3A gene in these phenotypes. We investigated chromatin and gene expression changes in blood and cell lines from three int dup(15) and three reciprocal AS deletion subjects to identify global genomic and gene expression changes that may influence both the AS and autism phenotypes. Using formaldehyde-assisted isolation of regulatory elements (FAIRE) we identified 1104 regions of differential open chromatin in AS deletion and 2344 regions int dup(15) indicating changes in chromatin could influence gene expression in these regions. Microarray analysis revealed 1225 genes that were elevated in AS deletion vs int dup(15) and 976 genes that were elevated in int dup(15) vs AS deletion PBMC (pvalue<0.05). Significant differences in expression were found for genes at the 15q locus like UBE3A, ATP10A and HERC2. A larger set of genes involved in chromatin remodeling, DNA repair and neurogenesis were found, at FAIRE peaks in AS deletion samples but had increased transcription in int dup(15) samples. There was a significant enhancement for genes with FOXP1 binding sites in the int dup(15) gene set and elevated FOXP1 protein could be detected in the nucleus of int dup(15) as compared to AS deletion cell lines. This analysis provides the first insights into transcriptional changes which may unveil new sets of genes and pathways contributing to both AS and autism pathogenesis. Gene expression was performed using 100ng of total RNA from each subject as starting material for amplification and cRNA synthesis in accordance Affymetrix protocols (http://tinyurl.com/3j7dcp6). Hybridizations were performed to the Affy HumanGene_st_v1 chip and the signal data normalized using internal chip controls. Normalized expression data was then exported to a text file for subsequent expression analysis using the EXPANDER software analysis suite.
2014-10-09 | E-GEOD-32563 | biostudies-arrayexpress
Project description:Genomic rearrangements may cause both Mendelian and complex disorders. Currently, several major mechanisms causing genomic rearrangements have been proposed such as non-allelic homologous recombination (NAHR), non-homologous end joining (NHEJ), fork stalling and template switching (FoSTeS) and microhomology-mediated break-induced replication (MMBIR). However, to what extent these mechanisms contribute to gene-specific pathogenic copy-number changes (CNCs) remains understudied. Furthermore, only few studies resolved these pathogenic alterations at nucleotide-level resolution. Accordingly, our aim is to explore which mechanisms contribute to a large, unique set of locus-specific non-recurrent genomic rearrangements causing the genetic neurocutaneous disorder neurofibromatosis type 1 (NF1). Through breakpoint-spanning PCR as well as array Comparative Genomic Hybridization (aCGH), we have identified the breakpoints and characterized the likely rearrangement mechanism of the NF1 intragenic CNCs in 78 unrelated patients. Unlike the most typical recurrent rearrangements mediated by flanking low copy repeats (LCRs), NF1 intragenic CNCs have diverse breakpoint locations, and are characterized by different rearrangement mechanisms. We propose the DNA replication-based mechanisms comprising FoSTeS/MMBIR and serial replication stalling to be the predominant mechanism leading to NF1 intragenic CNCs. In addition to the loop of a 197-bp palindrome located in intron 40, four Alu elements located in intron 1, 2, 3 and 50 were also identified as significant intragenic rearrangement hotspots within the NF1 gene. However, no clear genotype-phenotype correlations could be identified among the NF1 patients carrying NF1 intragenic CNCs.
2015-07-30 | GSE64869 | GEO
Project description:MicroRNAs (miRNAs) play a pivotal role in the regulation of hematopoiesis and development of leukemia. Great interest emerged in modulating miRNA expression for therapeutic purposes. In order to identify miRNAs, which specifically suppress leukemic growth of AML with t(8;21), inv(16) or MLL-rearrangement by inducing differentiation, we conducted a miRNA expression profiling in a cohort of 90 cytogenetically characterized, de novo pediatric AML cases. Four miRNAs, specifically downregulated in MLL-rearranged, t(8;21) or inv(16) AMLs, were characterized by their tumor suppressive properties in cell lines representing those respective cytogenetic groups. Among those, forced expression of miR-9 reduced leukemic growth and induced monocytic differentiation of t(8;21) AML cell lines in vitro and in vivo. The tumor suppressive functions of miR-9 were specifically restricted to AML cell lines and primary leukemic blasts with t(8;21). On the other hand, these functions were not evident in AML blasts from patients with MLL-rearrangements. We showed that miR-9 exerts its effects through the cooperation with let-7 to repress the oncogenic LIN28B/HMGA2 axis. Thus, miR-9 is a tumor suppressor-miR which acts in a stringent cell context-dependent manner. In order to identify miRNAs, which specifically suppress leukemic growth of AML with t(8;21) (n=21), inv(16) (n=17) or MLL-rearrangement (n=35) by inducing differentiation, we conducted a miRNA expression profiling in a cohort of 90 cytogenetically characterized, de novo pediatric AML cases, which also included 12 t(15;17) and 5 t(7;12) samples.
2014-01-01 | E-GEOD-52541 | biostudies-arrayexpress