Project description:SPO11-promoted DNA double-strand breaks (DSBs) formation is a crucial step for meiotic recombination, and it is indispensable to detect the broken DNA ends accurately for dissecting the molecular mechanisms behind. Here, we report a novel technique, named DEtail-seq (DNA End tailing followed by sequencing), that can directly and quantitatively capture the meiotic DSB 3’ overhang hotspots at single-nucleotide resolution.
Project description:In this study, to obtain a complete registry of genetic lesions in MDS and to identify novel therapeutic targets, we performed SNP array analysis and whole exome analysis for novel mutations using high-throughput sequencing technologies. In whole exome analysis, paired CD3-positive T cells were used as a normal control. By comparing sequences in tumors and paired T cells, 268 non-synonymous somatic mutations were confirmed with an overall true positive rate of 53.9 %, including 206 missense, 25 nonsense, and 10 splice site mutations, and 27 frameshift-causing insertions/deletions (indels). The mutations of the known gene targets, however, accounted for only 12.3 % of all detected mutations (N = 33), and the remaining 235 mutations involved previously unreported genes. Combined with the genomic copy number profile obtained by SNP array karyotyping, this array of somatic mutations provided a landscape of myelodysplasia genomes. Copy number analysis of Affymetrix 250K SNP arrays was performed for 29 MDS or related neoplasms and paired 29 germline samples.
Project description:In this study, to obtain a complete registry of genetic lesions in MDS and to identify novel therapeutic targets, we performed SNP array analysis and whole exome analysis for novel mutations using high-throughput sequencing technologies. In whole exome analysis, paired CD3-positive T cells were used as a normal control. By comparing sequences in tumors and paired T cells, 268 non-synonymous somatic mutations were confirmed with an overall true positive rate of 53.9 %, including 206 missense, 25 nonsense, and 10 splice site mutations, and 27 frameshift-causing insertions/deletions (indels). The mutations of the known gene targets, however, accounted for only 12.3 % of all detected mutations (N = 33), and the remaining 235 mutations involved previously unreported genes. Combined with the genomic copy number profile obtained by SNP array karyotyping, this array of somatic mutations provided a landscape of myelodysplasia genomes.
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.