Project description:Effect of FOXO knockdown on E2F1-mediated transcription U2OS cells stably expressing ER-E2F1 were infected with two different lentiviruses both targeting FOXO1 and FOXO3 or control virus encoding scrambled sequence. Twenty four hours post infection medium was replaced to serum-free DMEM for 24 hours. Then medium was replaced to serum-free DMEM with or without 20 nM 4-hydroxy tamoxifen for 6 hours.
Project description:Purpose: dose response analysis of E2F1 target genes expression in flow-sorted fractions with increasing amounts of fluorescently labled E2F1 Methods:U2OS pTRIPZ-YFP-ER-E2F1 cells were grown in full serum-containing growth medium and treated with 500 ng/ml doxycycline for 48 hours followed by addition of 90 nM OHT for an additional 20 hours. Cells from different YFP fractions were sorted by flow cytometry. mRNA profiles were generated by deep sequencing using Illumina HiSeq 4000. Results: different target genes have different E2F1 activation thresholds. Numerous proliferation-related target genes are induced already by the lowest E2F1-levels. Intermediate E2F1 levels induce cdk inhibitors, which might be responsible for cell cycle arrest. Finally, although some apoptotic E2F1 targets are induced already by low E2F1 levels, many key apoptotic genes require higher E2F1 levels for induction. Conclusions: induction of different cell fates by increasing E2F1 levels might pertain to differential affinities of the targets.
Project description:Experiment description To identify FoxM1-regulated genes, we carried out gene expression profile analysis after inducible activation of a FoxM1-ER fusion protein using high-density human cDNA microarrays. We constructed a stable line of U2OS cells expressing full-length HA-FoxM1 fused at its C-terminus to the ligand-binding domain of the estrogen receptor (ER), mutated such that it specifically responds to 4-hydroxytamoxifen (4-OHT) but not to estrogen. In the absence of 4-OHT the activity of the ER fusion protein is turned off, but can be rapidly induced when cells are exposed to 4-OHT. We isolated total RNA from untreated cultures and cultures treated with 4-OHT for 6 or 16 hr. As activation of FoxM1 results in accumulation of cells in G2/M, we additionally analyzed the induction of gene expression by FoxM1 in G1/S-synchronized cells by a thymidine block. Total RNA derived from untreated or stimulated FoxM1-ER cells was amplified, reverse transcribed, labeled and hybridized to cDNA microarrays containing 18,000 cDNAs and expressed sequence tags (ESTs). Bound cDNA was detected using Cy3 or Cy5 dyes. In each independent experiment we included reverted color controls (Cy3 (4-OHT treated); Cy5 (untreated) or Cy3 (untreated); Cy5 (treated)) and the expression profile was expressed as a Cy5:Cy3 ratio.
Project description:Previous studies of E2F family members have suggested that protein-protein interactions may be the mechanism by which E2Fs are recruited to specific genomic regions. We have addressed this hypothesis on a genome-wide scale using ChIP-seq analysis of MCF7 cell lines that express tagged wildtype and mutant E2F1 proteins. First, we performed ChIP-seq for tagged wt E2F1. Then, we analyzed E2F1 proteins that lacked the N terminal SP1 and cyclin A binding domains, the C terminal transactivation and pocket protein binding domains, and the internal marked box domain. Surprisingly, we found that the ChIP-seq patterns of the mutant proteins were identical to that of wt E2F1. However, mutation of the DNA binding domain abrogated all E2F1 binding to the genome. These results suggested that the interaction between the E2F1 DNA binding domain and a consensus motif may be the primary determinant of E2F1 recruitment. To address this possibility, we analyzed the in vivo binding sites for the in vitro-derived consensus E2F1 motif (TTTSSCGC) and also performed de novo motif analysis. We found that only 12% of the ChIP-seq peaks contained the TTTSSCGC motif. De novo motif analysis indicated that most of the in vivo sites lacked the 5M-CM-"M-BM-^@M-BM-^Y half of the in vitro derived consensus, having instead the in vivo consensus of CGCGC. In summary, our findings do not provide support for the model that protein-protein interactions are involved in recruiting E2F1 to the genome, but rather suggest that recognition of a motif found at most human promoters is the critical determinant. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf 9 total ChIP-seq datasets; four different HA-ER-E2F1 mutants, and one HA ER E2F1 wild type dataset done in duplicate, from 5 different stable cell lines derived from MCF7 cells; Three Input replicates from 2 different stable cell lines derived from MCF7 cells; HA ER E2F1 wild type duplicate dataset from MCF7 stable cells; 1 HA ER E2F1 DBDmut replicate from MCF7 stable cells cells, 1 HA ER E2F1M-CM-^NM-BM-^TC replicate from MCF7 stable cells cells, 1 HA ER E2F1M-CM-^NM-BM-^TN/C replicate from MCF7 stable cells cells, 1 HA ER E2F1M-CM-^NM-BM-^TMB replicate from MCF7 stable cells cells, 1 HA ER E2F1M-CM-^NM-BM-^TMB replicate from MCF7 stable cells cells, 3 Input replicates from MCF7 stable cells cells.
Project description:E2F1 induces numerous genes, including transcription factors, upon activation. The transcription factors then further cooperates with E2F1 to regulate the target genes and enhance the transcriptional effect. We used microarrays to analyze genes upregulated upon E2F1 activation by OHT with and without knockdown of NFYB and identified genes that are targets of both transcription factors.
Project description:ER:RAS-G12V expressing IMR90 cells were treated with either 100nM 4-OHT or 40uM Celecoxib or both for 6 days leading to RAS-induced senescence (RIS) with or without COX2 inhibition.
Project description:Transcriptional profiling of p16-induced senescent human diploid fibroblasts compared with proliferating cells. TIG-3 ER-p16 cells (primary normal human diploid fibroblasts expressing a 4-hydroxytamoxifen(4-OHT) regulatable form of human p16) were cultured for 7 days with or without 4-OHT. Total RNA was isolated using TRIzol reagent and were analyzed using the hum
Project description:We profiled gene expression and splicing changes in MCF-10A human mammary epithelial cells expressing MYC fused to a portion of estrogen receptor (MYC-ER) (Eilers et al., 1989; Littlewood et al., 1995). We performed RNA-seq, in triplicate, on 3D-grown MCF-10A MYC-ER cells at 0, 8, and 24 hours (h) after 4-OHT-induced MYC activation. As a control for 4-OHT-induced effects, 3D-grown parental MCF-10A cells lacking the MYC-ER fusion protein were treated with 4-OHT at the same timepoints.