Project description:Nascent strand were purified with either the BrdU or the lambda exonuclease methods from culture human basophilic erythroblasts and sequenced/ Two methods were compared to isolated the Nascent strand, lambda exonuclease digestion or immunoprecipitation after pulse labelling with BrdU The following files were generated by combining round 1 and 2 sample files; FNY01_2_2_Ery_NS_BrdU_macs_summits.bed FNY01_2_2_Ery_NS_BrdU_macs_peaks.bed FNY01_2_2_Ery_NS_lexo_macs_peaks.bed FNY01_2_2_Ery_NS_lexo_macs_summits.bed
Project description:Nascent strand were purified with either the BrdU or the lambda exonuclease methods from culture human basophilic erythroblasts and sequenced/
Project description:Reads from massively parallel sequencing of RNA primed, short nascent strands from asynchronously growing cancer cells (K562, MCF7). Newly replicated DNA was isolated based on size (400-800 bp) and the presence of a short RNA stretch at the 5' end using lambda exonuclease. Purified nascent strands were analyzed using massively parallel sequencing. Sheared genomic DNA was sequenced as a control.
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:Characterizing and controlling intrinsic biases of Lambda exonuclease in nascent strand sequencing reveals phasing between nucleosomes and G-quadruplex motifs around a subset of human replication origins
Project description:DNA polymerase epsilon (Pole) carries out leading strand synthesis with high fidelity owing to its exonuclease activity. Pole polymerase and exonuclease activities are in balance, due to partitioning of nascent strands between catalytic sites, so that net end resection occurs when synthesis is impaired. Stalling of chromosomal DNA synthesis activates replication checkpoint kinases, required to preserve the functional integrity of replication forks. We found that Pole is phosphorylated in a Rad53CHK1-dependent manner upon fork stalling, likely to limit Pole-driven nascent strand resection that causes replication fork collapse. In stress conditions Pole phosphorylation occurs on serine 430 of the Pol2 catalytic subunit. A S430 phosphomimic limits strand partitioning and exonucleolytic processivity, while non-phosphorylatable Pol2-S430A bypasses checkpoint regulation causing stalled fork resection and collapse. We propose that checkpoint kinases switch Pole to an exonuclease-safe mode by curbing active site partitioning thus preventing nascent strand resection and stabilizing stalled replication forks.
Project description:Nascent strand were purified with the BrdU methods from culture human basophilic erythroblasts and sequenced. An allele-specific analysis of origin of replication efficiency was performed by taking advantage of the phased genome sequence of an individual
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.