Project description:Although Runt-related transcription factor 1 (RUNX1) has been generally considered to be a tumor suppressor, a growing body of evidence strongly suggests its pro-oncogenic property in acute myeloid leukemia (AML), Here we demonstrate that anti-leukemic effect mediated by RUNX1 depletion is highly dependent on a functional p53-mediated cell death pathway. Based on our present findings, anti-tumor effect elicited by RUNX1 silencing was compensated by the other RUNX family members such as RUNX2 and RUNX3, and a simultaneous attenuation of whole RUNX family members as a cluster displayed a much stronger anti-tumor effect relative to their individual suppression. Notably, switching off RUNX cluster utilizing the novel alkylating agent-conjugated pyrrole-imidazole (PI) polyamides, which specifically bound to the consensus RUNX-binding sequences, was highly effective against leukemia as well as dismal-prognostic solid tumors arising from diverse origins in vivo without any significant adverse events. Together, this work identifies the crucial role of RUNX cluster in the maintenance and the progression of cancer cells, and the indicated gene switch technology-dependent its modulation would be a novel strategy to control malignancies.
Project description:The Runx genes are important in development and cancer, where they can act either as oncogenes or tumour supressors. We compared the effects of ectopic Runx expression in established fibroblasts, where all three genes produce an indistinguishable phenotype entailing epithelioid morphology and increased cell survival under stress conditions. Gene array analysis revealed a strongly overlapping transcriptional signature, with no examples of opposing regulation of the same target gene. A common set of 50 highly regulated genes was identified after further filtering on regulation by inducible RUNX1-ER. This set revealed a strong bias toward genes with annotated roles in cancer and development, and a preponderance of targets encoding extracellular or surface proteins reflecting the marked effects of Runx on cell adhesion. Experiment Overall Design: 6 samples (expression of different Runx family members); 5 in duplicate, 1 single. 2 control samples (empty vector) in duplicate. Cultures of Runx expressing cells were grown to confluence, treated with ethanol +/- 4OHT tamoxifen for 24 hours and harvested for RNA extraction and hybridization on Affymetrix microarrays
Project description:The Runx genes are important in development and cancer, where they can act either as oncogenes or tumour supressors. We compared the effects of ectopic Runx expression in established fibroblasts, where all three genes produce an indistinguishable phenotype entailing epithelioid morphology and increased cell survival under stress conditions. Gene array analysis revealed a strongly overlapping transcriptional signature, with no examples of opposing regulation of the same target gene. A common set of 50 highly regulated genes was identified after further filtering on regulation by inducible RUNX1-ER. This set revealed a strong bias toward genes with annotated roles in cancer and development, and a preponderance of targets encoding extracellular or surface proteins reflecting the marked effects of Runx on cell adhesion. Keywords: Comparative study of gene targets regulated by overexpression of the different Runx family members
Project description:The regulatory mechanism for filamentation includes a complex network of transcription factors that play roles in regulating hyphae associated genes. We identify here a new regulator of filamentation from the zinc cluster transcription factor family. We present evidence suggesting that this transcription factor assists the Nrg1/Brg1 switch regulating hyphal development.
Project description:The replication of eukaryotic chromosomes is organized temporally and spatially within the nucleus through epigenetic regulation of replication origin function. The characteristic initiation timing of specific origins is thought to reflect their chromatin environment or sub-nuclear positioning, however the mechanism remains obscure. Here we show that the yeast Forkhead transcription factors, Fkh1 and Fkh2, are global determinants of replication origin timing. Forkhead regulation of origin timing is independent of local levels or changes of transcription. Instead, we show that Fkh1 and Fkh2 are required for the clustering of early origins and their association with the key initiation factor Cdc45 in G1-phase, suggesting that Fkh1 and Fkh2 selectively recruit origins to emergent replication factories. Fkh1 and Fkh2 bind Fkh-activated origins, and interact physically with ORC, providing a plausible mechanism to cluster origins. These findings add a new dimension to our understanding of the epigenetic basis for differential origin regulation and its connection to chromosomal domain organization.
Project description:The replication of eukaryotic chromosomes is organized temporally and spatially within the nucleus through epigenetic regulation of replication origin function. The characteristic initiation timing of specific origins is thought to reflect their chromatin environment or sub-nuclear positioning, however the mechanism remains obscure. Here we show that the yeast Forkhead transcription factors, Fkh1 and Fkh2, are global determinants of replication origin timing. Forkhead regulation of origin timing is independent of local levels or changes of transcription. Instead, we show that Fkh1 and Fkh2 are required for the clustering of early origins and their association with the key initiation factor Cdc45 in G1-phase, suggesting that Fkh1 and Fkh2 selectively recruit origins to emergent replication factories. Fkh1 and Fkh2 bind Fkh-activated origins, and interact physically with ORC, providing a plausible mechanism to cluster origins. These findings add a new dimension to our understanding of the epigenetic basis for differential origin regulation and its connection to chromosomal domain organization.
Project description:The replication of eukaryotic chromosomes is organized temporally and spatially within the nucleus through epigenetic regulation of replication origin function. The characteristic initiation timing of specific origins is thought to reflect their chromatin environment or sub-nuclear positioning, however the mechanism remains obscure. Here we show that the yeast Forkhead transcription factors, Fkh1 and Fkh2, are global determinants of replication origin timing. Forkhead regulation of origin timing is independent of local levels or changes of transcription. Instead, we show that Fkh1 and Fkh2 are required for the clustering of early origins and their association with the key initiation factor Cdc45 in G1-phase, suggesting that Fkh1 and Fkh2 selectively recruit origins to emergent replication factories. Fkh1 and Fkh2 bind Fkh-activated origins, and interact physically with ORC, providing a plausible mechanism to cluster origins. These findings add a new dimension to our understanding of the epigenetic basis for differential origin regulation and its connection to chromosomal domain organization. These files contain BrdU-IP-seq files (2 replicates for each strain; 5 strains total where WT was used as control). These files also contain RNA-seq data from Asynchronous and G1 arrested WT and Mutant cells (2 replicates per strain and condition; paired end). These files also contain RNA-pol-chip-seq data from Asynchronous and G1 arrested WT and Mutant cells (2 replicates per strain/condition).
Project description:The HIV-1 accessory protein Vif hijacks a cellular Cullin-RING ubiquitin ligase, CRL5, to promote degradation of the APOBEC3 (A3) family of restriction factors. Recently, the cellular transcription cofactor CBFb was shown to form a complex with CRL5-Vif and to be essential for A3 degradation and viral infectivity. We now demonstrate that CBFb is required for assembling a well-ordered CRL5-Vif complex by inhibiting Vif oligomerization and by activating CRL5-Vif via direct interaction. The CRL5-Vif-CBFb holoenzyme forms a welldefined heterohexamer, indicating that Vif simultaneously hijacks CRL5 and CBFb. Heterodimers of CBFb and RUNX transcription factors contribute toward the regulation of genes, including those with immune system functions. We show that binding of Vif to CBFb is mutually exclusive with RUNX heterodimerization and impacts the expression of genes whose regulatory domains are associated with RUNX1. Our results provide a mechanism by which a pathogen with limited coding capacity uses one factor to hijack multiple host pathways. Identification of RUNX1 binding sites in the Jurkat cell line
Project description:MiRNAs, which are a family of small non-coding RNAs, regulate a broad array of physiological and developmental processes. However, their regulatory roles have remained largely mysterious. E2F is a positive regulator of cell cycle progression and also a potent inducer of apoptosis. Positive feedback loops in the regulation of Rb-E2F pathway are predicted and shown experimentally. Recently, it has been discovered that E2F induce a cluster of miRNAs called miR449. In turn, E2F is inhibited by miR449 through regulating different transcripts, thus forming negative feedback loops in the interaction network. Here, based on the integration of experimental evidence and quantitative data, we studied Rb-E2F pathway coupling the positive feedback loops and negative feedback loops mediated by miR449. Therefore, a mathematical model is constructed based in part on the model proposed in Yao-Lee et al. (2008) and nonlinear dynamical behaviors including the stability and bifurcations of the model are discussed.
Project description:The HIV-1 accessory protein Vif hijacks a cellular Cullin-RING ubiquitin ligase, CRL5, to promote degradation of the APOBEC3 (A3) family of restriction factors. Recently, the cellular transcription cofactor CBFb was shown to form a complex with CRL5-Vif and to be essential for A3 degradation and viral infectivity. We now demonstrate that CBFb is required for assembling a well-ordered CRL5-Vif complex by inhibiting Vif oligomerization and by activating CRL5-Vif via direct interaction. The CRL5-Vif-CBFb holoenzyme forms a wellde?ned heterohexamer, indicating that Vif simultaneously hijacks CRL5 and CBFb. Heterodimers of CBFb and RUNX transcription factors contribute toward the regulation of genes, including those with immune system functions. We show that binding of Vif to CBFb is mutually exclusive with RUNX heterodimerization and impacts the expression of genes whose regulatory domains are associated with RUNX1. Our results provide a mechanism by which a pathogen with limited coding capacity uses one factor to hijack multiple host pathways. Analysis of Vif-dependent effects on gene expression in Jurkats when cells are activated for 4 or 6 hours with PMA and PHA