Homo sapiens
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ABSTRACT:
PROVIDER: PRJNA272418 | ENA |
REPOSITORIES: ENA
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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: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. Patient DNA samples with non-overlapping CNCs, as estimated by MLPA, were labeled with Cy3 and Cy5 fluorophores respectively, and hybridized onto the microarray. Alternatively, patient DNA was hybridized versus unrelated individual blood DNA. No hybridizations using biological replicates were performed. In total 6 samples were included. Please note that our experimental setup included a hybridization in which two DNA samples with non-overlapping deletions, from two NF1 patients, were hybridized in one experiment (sample codes: 1253 and 1403). In this specific case, assigning test or reference function to the samples was a matter of arbitrary choice. However, if needed, sample 1253 can be denoted as test, and sample 1403 can be denoted as reference in this experiment.
2015-07-30 | E-GEOD-64869 | biostudies-arrayexpress
Project description:Somatic copy number changes in cNFs samples in NF1 patients
2014-05-28 | GSE58000 | GEO
Project description:Comparison of copy number changes in MPNST samples against benign neurofibromas in NF1 patients
2009-05-20 | GSE16041 | GEO
Project description:DNA copy number changes in malignant mesothelioma
| PRJNA230026 | ENA
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| PRJNA143465 | ENA
Project description:DNA copy number changes in prostate cancer cell lines
| PRJNA104595 | ENA
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
| S-EPMC2531291 | biostudies-literature