Project description:The regulation of replication-dependent histone genes by CASP8AP2 and NPAT is likely direct, based on ChIP-seq. CASP8AP2 and NPAT ChIP-Seq peaks were enriched near transcription start sites (TSSs) of replication-dependent, but not replication-independent histone genes on chromosomes 1, 6 and 12 in both cell lines. HINFP ChIP-Seq peaks were enriched near transcription start sites (TSSs) of replication-dependent histone genes H4 and H2B and replication-independent histone genes H1FX and H1F0 in both cell lines. Another histone gene regulator, E2F1 also bound to TSSs of many histone genes mainly replication-independent. Examination of histone genes transcroption regulators binding by ChIP-seq in normal and cancer cell lines
Project description:During cell division, transcription factors (TFs) are removed from chromatin twice, during DNA synthesis, and during condensation of chromosomes. How TFs can efficiently find their sites following these stages has been unclear. Here, we have analyzed the binding pattern of expressed TFs in human colorectal cancer cells. We find that binding of TFs is highly clustered, and that the clusters are enriched in binding motifs for several major TF classes. Strikingly, almost all clusters are formed around cohesin, and loss of cohesin decreases both DNA accessibility and binding of TFs to clusters. We show that cohesin remains bound in S phase, holding the nascent sister chromatids together at the TF cluster sites. Furthermore, cohesin remains bound to the cluster sites when TFs are evicted in early M-phase. These results suggest that cohesin binding functions as a cellular memory that promotes re- stablishment of TF clusters after DNA replication and chromatin condensation. Examination of TF binding by ChIP-seq in a CRC cell-line.
Project description:During cell division, transcription factors (TFs) are removed from chromatin twice, during DNA synthesis, and during condensation of chromosomes. How TFs can efficiently find their sites following these stages has been unclear. Here, we have analyzed the binding pattern of expressed TFs in human colorectal cancer cells. We find that binding of TFs is highly clustered, and that the clusters are enriched in binding motifs for several major TF classes. Strikingly, almost all clusters are formed around cohesin, and loss of cohesin decreases both DNA accessibility and binding of TFs to clusters. We show that cohesin remains bound in S phase, holding the nascent sister chromatids together at the TF cluster sites. Furthermore, cohesin remains bound to the cluster sites when TFs are evicted in early M-phase. These results suggest that cohesin binding functions as a cellular memory that promotes re- stablishment of TF clusters after DNA replication and chromatin condensation. Examination of TF binding by ChIP-seq in LoVo CRC cell-lines.
Project description:Gene-expression in siRNA treated U2OS and hTERT-RPE1 cells showed that CASP8AP2, NPAT and HINFP do not regulate expression of each other, and do not have any common target genes, except histones. Most histone genes are downregulated in U2OS cells following loss of CASP8AP2, NPAT or HINFP. In normal cells, highly-expressed histone genes were downregulated, albeit less than in tumor cells following loss of CASP8AP2. The p53 target genes were upregulated relatively late, clearly after the changes in expression of histone genes were observed. U2OS and hTERT-RPE1 cells were treated with CASP8AP2, NPAT, HINFP or control siRNA in duplicates or triplicates and collected for RNA purification on 1st, 2nd and 3d days.
Project description:During cell division, transcription factors (TFs) are removed from chromatin twice, during DNA synthesis, and during condensation of chromosomes. How TFs can efficiently find their sites following these stages has been unclear. Here, we have analyzed the binding pattern of expressed TFs in human colorectal cancer cells. We find that binding of TFs is highly clustered, and that the clusters are enriched in binding motifs for several major TF classes. Strikingly, almost all clusters are formed around cohesin, and loss of cohesin decreases both DNA accessibility and binding of TFs to clusters. We show that cohesin remains bound in S phase, holding the nascent sister chromatids together at the TF cluster sites. Furthermore, cohesin remains bound to the cluster sites when TFs are evicted in early M-phase. These results suggest that cohesin binding functions as a cellular memory that promotes re- stablishment of TF clusters after DNA replication and chromatin condensation. Examination of TF binding by ChIP-seq in a CRC cell-line treated with non-targeting siRNA, or siRNA specific to the cohesin subunit RAD21.
Project description:Cross-linking mass spectrometry (XL-MS) has progressed from studying purified protein assemblies in-vitro towards investigating the same assemblies in intact cells, tissues, and even whole organisms (so called “in situ XL-MS”). In situ XL-MS offers the great advantage of reporting on the architectures of protein complexes as they occur inside cells and tissues. Here we developed a complete workflow of in-situ XL-MS followed by purification, and employ it to investigate SARS-CoV2 protein inside the host cell. We focused on three Sars-Cov-2 proteins for which the structural information is either missing or incomplete: NSP1, NSP2, and the Nucleocapsid protein (N protein). Relatively little is known about the structures of these specific proteins, which was our motivation for choosing them. We were able to identify considerable cross-link sets, of in-situ origin. Integration of the cross-links with additional structural information allowed us to build almost complete models for NSP2 and the N protein.
Project description:This study aimed to explore the role of the Zyxin-related protein TRIP6 (thyroid receptor interacting protein 6) in Ewing's sarcoma (ES). By interrogation of published miccroarray data, we observed that of all seven Zyxin-proteins only TRIP6 is highly overexpressed in ES compared to normal tissues. RNA interference experiments and subsequent microarray and gene-set enrichment analyses indicated that TRIP6 expression is associated wth a pro-proliferative and pro-invasive transcriptional signature. Consistently, functional assays demonstrated that TRIP6 promotes migration, invasion, long-term proliferation and clonogencity of ES cells. A673 and SK-N-MC Ewing sarcoma cells were transfected with specific siRNA against TRIP6 (siTRIP6_4 or siTRIP6_5) or negative control siRNA (siControl) or Mock-transfected.
Project description:Effects of genetic modification of trans-acting transcription factors and a chromatin remodeler on noncoding RNA transcription and trans-acting factor binding at loci in yeast.
Project description:A comparative ChIP-chip analysis of TFIIB and NC2 in human B cells reveals that basal core promoter architectures control the equilibrium between NC2 and preinitiation complexes. We conducted a comparative ChIP-chip and gene expression analysis of TFIIB in human B cells and analyze associated core promoter architectures. TFIIB occupancy relates well to gene expression, with the vast majority of promoters being GC-rich and lacking defined core promoter elements. TATA consensus and TATA-like motifs but not the previously in vitro defined TFIIB recognition elements (BREs) are enriched in approximately 5% of the genes. Further insight was obtained by performing a parallel ChIP-chip analysis of the TFIIB antagonist NC2. The latter identifies a highly related target gene set. Nonetheless, subpopulations show strong variations in TFIIB/NC2 ratios, with high NC2/TFIIB ratios correlating to promoters that show dispersed transcription start site patterns and lacking defined core elements. Conversely, high TFIIB/NC2 ratios select for conserved core promoter elements that include TATA and INR (initiator), the upstream TFIIB recognition element (BREu) and the downstream promoter element (DPE). Two biological samples from LCL 721 lymphoblastoid human B cells were subjected to ChIP-chip analysis of TFIIB and NC2 using a Nimblegen human promoter array (based on the HG17 genome build) covering 1.5 kb DNA around transcription start sites.
Project description:Cleavage factor II (CF II) is a poorly characterized component of the multi-protein complex catalyzing 3' cleavage and polyadenylation of mammalian mRNA precursors. We have reconstituted CF II as a heterodimer of hPcf11 and hClp1. The heterodimer is active in partially reconstituted cleavage reactions, whereas hClp1 by itself is not. Pcf11 moderately stimulates the RNA 5' kinase activity of hClp1; the kinase activity is dispensable for RNA cleavage. CF II binds RNA with nanomolar affinity. Binding is mediated mostly by the two zinc fingers in the C-terminal region of hPcf11. RNA is bound without pronounced sequence-specificity, but extended G-rich sequences appear to be preferred. We discuss the possibility that CF II contributes to the recognition of cleavage/polyadenylation substrates through interaction with G-rich far-downstream sequence elements.