Project description:We performed RNA-seq in cells synchronized to S or G2 phase to identify genes that were transcriptionally regulated by ATR activity.
Project description:To identify the component(s) involved in cell cycle control in the protozoan Giardia lamblia, cells arrested at the G1- or G2-phase by treatment with nocodazole and aphidicolin were prepared from the synchronized cell cultures. RNA-sequencing analysis of the two stages of Giardia cell cycle identified several cell cycle genes that were up-regulated at the G2-phase. This result indicates that the cell cycle machinery operates in this protozoan, one of the earliest diverging eukaryotic lineages.
Project description:Microarray data from G2-synchronized p53(+) and p53(-) fibroblasts before and after 3 h release from cell cycle blockade in the presence of 5 µM sodium arsenite. Keywords: Gene induction
Project description:Gene expression must be reconfigured rapidly during the subsequent phases of the cell cycle to execute the cellular functions specific of each phase. Post-transcriptional regulation has a predominant role in modulating gene expression during the mitotic cell cycle, including among other mechanisms, protein phosphorylation and ubiquitination, differential protein stability and mRNA localization and translatability. Regulation at the transcriptional level is also important, as studies conducted in synchronized plant cell suspension cultures have identified hundreds of genes with periodic patterns of genes expression across the phases of the cell cycle. We describe here an alternative strategy to cell suspension cultures to profile the transcriptome of Arabidopsis root cells in the G2/M phase of the cell cycle. Through fluorescence activated cell sorting we first isolated cells in G2/M using CYCB1;1-GFP, a reporter of a mitotic cyclin. The analysis of the transcriptome of these cells allowed us to identify hundreds of genes whose expression is depleted or enriched in G2/M cells.
Project description:To characterize the downstream gene expression response following ATR inhibition, we performed RNA-Seq after treatment of CLB-BAR and CLB-GE neuroblastoma cells with 50 nM of the ATR inhibitor BAY 1895344 for 24h and 48h
Project description:We compared the poly(A) tail length status of mRNAs of HeLa cells between two phases of the mitotic cell cycle: S and G2/M phases. Hundreds of mRNAs were found to be regulated by changes in their poly(A) tail length during mitotic cell cycle in a phase specific manner. Many of these differentially polyadenylated mRNAs encode proteins related to cell death, cell cycle and cellular growth and proliferation. HeLa cells were synchronized with double thymidine blockade (12 hours with 2 mM thymidine, 12 hours release, and 12 hours with 2 mM thymidine), and samples were taken after 2 hours release (S phase) and 8 hours release (G2/M phase). For each condition total RNA was purified by two different procedures: poly(U) chromatography and oligo(dT)-chromatography. Poly(U)-chromatography (Jacobson, 1987): 100 μg of total RNA were bound to poly(U)-sepharose (Sigma) and eluted at 35ºC to isolate mRNAs with short poly(A) tail (<30As, SHORT fraction). Oligo(dT) chromatography: mRNAs were purified independently of their poly(A) tail length with Ambion Poly(A)Purist kit from 20 μg total RNA (ALL fraction). Jacobson, A. Purification and fractionation of poly(A)+ RNA. Methods in Enzymology (1987) 152: 254-261. Keywords: time course Comparison of ALL fraction mRNAs and SHORT fraction mRNAs measured after 2 hours (S phase) and 8 hours release (G2/M) from double thymidine blockade; 3 biological replicates at each of the two time points; two technical replicates with dye swapping per comparison.
Project description:To understand the in vivo transcriptomic response to ATR inhibition, RNA-Seq was performed after treatment of 2 previously developed neuroblastoma mouse models (Alk-F1178S;Th-MYCN and Rosa26_Alkal2;Th-MYCN; see Borenas et al., EMBO J, 2021) with the ATR inhibitor BAY 1895344.
Project description:The ATR kinase, which coordinates cellular responses to DNA replication stress, is also essential for the proliferation of normal unstressed cells. Although its role in the replication stress response is well defined, the mechanisms by which ATR supports normal cell proliferation remain elusive. Here, we show that Atr is dispensable for the viability of G0-arrested naïve B cells. However, upon cytokine-induced proliferation, Atr-deficient B cells initiate DNA replication efficiently in early S phase, but by mid-S phase they display dNTP depletion, fork stalling, and replication failure. Nonetheless, productive DNA replication can be restored in Atr-deficient cells by pathways that suppress origin firing, such as downregulation of CDC7 and CDK1 kinase activities. Together, these findings indicate that ATR supports the proliferation of normal unstressed cells by tempering the pace of origin firing during the early S phase to avoid exhaustion of dNTPs and other replication factors.
Project description:The actin-related proteins (ARPs) comprise a conserved protein family. Arp4p is found in large multisubunits of the INO80 and SWR1 chromatin remodeling complexes and in the NuA4 histone acetyltransferase complex. Here we show that arp4 (arp4S23AD159A) temperature-sensitive cells are defective in G2/M phase function. arp4 mutants are sensitive to the microtubule depolymering agent benomyl and arrest at G2/M phase at restrictive temperature. Arp4p is associated with centromeric and telomeric regions throughout cell cycle. Ino80p, Esa1p, and Swr1p, components of the INO80, NuA4, and SWR1 complexes, respectively, also associate with centromeres. The association of many kinetochore components including Cse4p, a component of the centromere nucleosome, Mtw1p, and Ctf3p is partially impaired in arp4 cells, suggesting that the G2/M arrest of arp4 mutant cells is due to a defect in formation of the chromosomal segregation apparatus. Keywords: ChIP-chip ⢠The goal of the experiment Genome-wide localization of Arp4 binding sites in Saccharomyces cerevisiae ⢠Experimental factors Distribution of Arp4 in WT in G2/M phase in the presence of nocodazole (Saccharomyces cerevisiae). ⢠Experimental design ChIP analysis: Hybridization data for ChIP fraction was compared with WCE (whole cell extract) fraction. Chromosome III, IV,V,VI S. cerevisiae: SC3456a520015F, P/N# 520015, affymetrix tiling array were used.
Project description:The ATR kinase, which coordinates cellular responses to DNA replication stress, is also essential for the proliferation of normal unstressed cells. Although its role in the replication stress response is well defined, the mechanisms by which ATR supports normal cell proliferation remain elusive. Here, we show that Atr is dispensable for the viability of G0-arrested naïve B cells. However, upon cytokine-induced proliferation, Atr-deficient B cells initiate DNA replication efficiently in early S phase, but by mid-S phase they display dNTP depletion, fork stalling, and replication failure. Nonetheless, productive DNA replication can be restored in Atr-deficient cells by pathways that suppress origin firing, such as downregulation of CDC7 and CDK1 kinase activities. Together, these findings indicate that ATR supports the proliferation of normal unstressed cells by tempering the pace of origin firing during the early S phase to avoid exhaustion of dNTPs and other replication factors.