Project description:Transient obstruction of DNA polymerase progression activates the ATR checkpoint kinase, which suppresses fork breakage, strand resection, and RPA accumulation. Herein, we use a developed DNA break-detection assay, BrITL, to identify replication-problematic loci that become processed into persistent double-strand breaks across the human genome from ATR inhibition.
Project description:Transient obstruction of DNA polymerase progression activates the ATR checkpoint kinase, which suppresses fork breakage, strand resection, and RPA accumulation. Herein, we use RPA ChIP-Seq to identify replication-problematic loci (RPLs) across the mammalian genome from ATR inhibition.
Project description:Transient obstruction of DNA polymerase progression activates the ATR checkpoint kinase, which suppresses fork breakage, strand resection, and RPA accumulation. Herein, we use a developed DNA break-detection assay, BrITL, to identify replication-problematic loci (RPLs) that become processed into persistent double-strand breaks across the mammalian genome from ATR inhibition.
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:Dicer, RNase III endonuclease, is an essential enzyme in miRNA biogenesis that regulates target gene expression, and it has been reported that aberrant expressions of Dicer associate with the clinical outcomes of patients in various cancers. To explore the miRNA differencial expression regulated by Dicer in MDA-MB-231/E1A cells, the microarray profiling analysis was employed to conduct differentially expressed miRNAs in stable MDA-MB-231/vector, MDA-MB-231/E1A, and MDA-MB-231/E1A/shDicer cells.
Project description:Dicer, RNase III endonuclease, is an essential enzyme in miRNA biogenesis that regulates target gene expression, and it has been reported that aberrant expressions of Dicer associate with the clinical outcomes of patients in various cancers. To explore the miRNA differencial expression regulated by Dicer in MDA-MB-231/E1A cells, the microarray profiling analysis was employed to conduct differentially expressed miRNAs in stable MDA-MB-231/vector, MDA-MB-231/E1A, and MDA-MB-231/E1A/shDicer cells. The four groups including vector control, E1A-expressing and Dicer knockdown in E1A-expressing MDA-MB-231 cells were harvested and RNA were isolated. Two independent experiments were performed for each group.
Project description:Identification of genes that are involved in self-seeding by comparing gene expression profiles between parental MDA-MB-231 cells and seeder cells (MDA-231-S1a and S1b) 2 replicates from each sample (parental MDA-MB-231, MDA-MB-231 S1a and MDA-MB-231 S1b) were analyzed