Project description:Chromosome conformation-capture technologies are widely used in 3D genomics; however, experimentally, such methods have high-noise limitations and, therefore, require significant bioinformatics efforts to extract reliable distal interactions. Miscellaneous undesired linear DNAs, present during proximity-ligation, represent a main noise source which needs to be minimized or eliminated. In this study, different exonuclease combinations were tested to remove linear DNA fragments from a circularized DNA preparation. This method efficiently removed linear DNAs, raised the proportion of annulation and increased valid-pairs ratio from 30-40% to 70-80% for enhanced interaction detection in standard Hi-C. This strategy is applicable for development of various 3D genomics technologies, or optimization of Hi-C sequencing efficiency.
Project description:Chromosome conformation-capture technologies are widely used in 3D genomics; however, experimentally, such methods have high-noise limitations and, therefore, require significant bioinformatics efforts to extract reliable distal interactions. Miscellaneous undesired linear DNAs, present during proximity-ligation, represent a main noise source, which needs to be minimized or eliminated. In this study, different exonuclease combinations were tested to remove linear DNA fragments from a circularized DNA preparation. This method efficiently removed linear DNAs, raised the proportion of annulation and increased the valid-pairs ratio from ?40% to ?80% for enhanced interaction detection in standard Hi-C. This strategy is applicable for development of various 3D genomics technologies, or optimization of Hi-C sequencing efficiency.
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:The goal of this study is to reveal the role of the RNA editor-exonuclease axis during erythropoiesis. We bled E18.5 Zcchc6-/- and Dis3l2-/- mice and profiled transcriptome of their mature red blood cells/reticulocytes.
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:Chronic myeloid leukemia (CML), caused by BCR::ABL1 fusion gene, is known to regulate disease progression by altering the expression of genes. However, the molecular mechanisms underlying these changes are largely unknown. In this study, we identified RNA Exonuclease 5 (REXO5) as a novel gene with elevated mRNA expression levels in chronic myeloid leukemia (CML) patients. Additionally, using the REXO5 knockout (KO) K562 cell lines, we revealed a novel role for REXO5 in the DNA damage response (DDR). Compared to wild-type (WT) cells, REXO5 KO cells showed an accumulation of R-loops and increased DNA damage. We demonstrated that REXO5 translocates to sites of DNA damage through its RNA recognition motif (RRM) and selectively binds to R loops. Interestingly, we identified that REXO5 regulates R-loop levels by degrading mRNA within R-loop using its exonuclease domain. REXO5 KO showed ATR-CHK1 activation. Collectively, we demonstrated that REXO5 plays a key role in the physiological control of R-loops using its exonuclease domain. These findings may provide novel insights into how REXO5 expression contribute to CML pathogenesis.