Project description:A small number of transcription factors, including Oct-3/4 and Sox2, constitute the transcriptional network that maintains pluripotency in embryonic stem (ES) cells. Previous reports suggested that some of these factors form a complex that binds the Oct-Sox element, a composite sequence consisting of closely juxtaposed Oct-3/4-binding and Sox2-binding sites. However, little is known regarding the components of the complex. In this study, we show that Sall4, a member of the Spalt-like family of proteins, directly interacts with Sox2 and Oct-3/4. Sall4 in combination with Sox2 or Oct-3/4 simultaneously occupies the Oct-Sox elements in mouse ES cells. Sall4 knockdown led to differentiation of ES cells. Overexpression of Sall4 in ES cells increased reporter activities in a luciferase assay when the Pou5f1- or Nanog-derived Oct-Sox element was included in the reporter. Microarray analyses revealed that Sall4 and Sox2 bound to the same genes in ES cells significantly more frequently than expected from random coincidence. These factors appeared to bind the promoter regions of a subset of the Sall4- and Sox2-double-positive genes in precisely similar distribution patterns along the promoter regions, suggesting that Sall4 and Sox2 associate with such Sall4/Sox2-overlapping genes as a complex. Importantly, gene ontology analyses indicated that the Sall4/Sox2-overlapping gene set is enriched for genes involved in maintaining pluripotency. Sall4/Sox2/Oct-3/4-triple-positive genes identified by referring to a previous study identifying Oct-3/4-bound genes in ES cells were further enriched for pluripotency genes than Sall4/Sox2-double-positive genes. These results demonstrate that Sall4 contributes to the transcriptional network operating in pluripotent cells, together with Oct-3/4 and Sox2.
Project description:Genome-wide DNA methylation profiling of human B-ALL cell line SEM after 48 h incubation with DMSO (control), CX-4945 (Silmitasertib), Decitabine (DEC) or combined CX-4945 + DEC treatment. The Infinium MethylationEPIC BeadChip was used to obtain DNA methylation profiles across approximately 866,895 CpG islands.
Project description:MicroRNA expression profiling in matched lesional skin samples from 25 patients with psoriasis using the miRNA analysis platform miRCURY LNATM MicroRNA array (v. 11.0) (Exiqon). Aim: To explore the effect of three different preservation methods (Formalin-fixation paraffin-embedding (FFPE), frozen (FS) and OCT-embedding (OCT)) on miRNA expression levels in matched lesional skin samples from 25 patients with psoriasis.
Project description:Decitabine (DEC) has a known DNA demethylating activity but also cause cytotoxicity through DNA damage. The two differing mechanisms of action confound studies investigating the effect of DNA demethylation in cancer treatment. The novel DNA methyltransferase 1 specific inhibitor GSK-3685032 causes loss of DNA methylation without DNA damage and offers the possibility to examine the molecular consequences of global loss of DNA methylation. EM-seq was used to evaluate the DNA demethylating effects of DEC and GSK-3685032 in LOUCY and SUP-T1 cells treated with 10 nM Decitabine for 3 days or 300 nM of GSK-3685032 for 3 and 7 days.
Project description:Interaction of the Kaposi’s sarcoma-associated herpesvirus (KSHV) Rta protein with the cellular Notch signaling effector, Recombination Signaling Protein (RBP)-Jk (aka CSL and CBF-1), is essential for viral reactivation from latency. We previously showed that Rta binds to a DNA motif repeated in the viral Mta promoter (called “CANT” or Rta-c) to stimulate RBP-Jk DNA binding, and distinguished Rta from the activated Notch-1 protein. To determine whether Rta’s mechanism would apply generally to other viral promoters, we employed chromatin immunoprecipitation/deep sequencing (ChIP/Seq) to identify Rta and RBP-Jk binding sites across the KSHV genome. We show that RBP-Jk binds nearly exclusively to unique genome sites during latency and reactivation. Many, but not all, reactivation-specific RBP-Jk peaks were associated with Rta bound to single Rta-c motifs. Other motifs that were over-represented with stimulated RBP-Jk DNA binding including those for the cellular DNA binding proteins BCL11A, MNT, MAF B, and TCF12. Four of the top seven motifs that were most over-represented with inhibition of RBP-Jk DNA binding were putative binding sites for the Pit/Oct/Unc (POU) family of proteins, including POU3F3 (Oct-8) and POU5F1 (Oct-4). Interestingly, two other POU motifs, including one for the POU2F1 (Oct-1) protein, are associated with inhibition of RBP-Jk DNA binding unless Rta bound to a nearby Rta-c motif. The relative distances between the Rta-c, POU, and RBP-Jk motifs were conserved at reactivation-specific RBP-Jk peaks in three promoters that Rta transactivated, and the Rta-c and Oct-1 motifs overlapped in two of those. The proximity of the Rta-c/Oct-1 motif to an RBP-Jk motif is critical for Rta transactivation of the ORF50AS/KbZIP promoter, and knockdown of Oct-1 protein debilitated reactivation and production of infectious virus. Our data suggest a broad role for POU proteins in regulating DNA binding of RBP-Jk and its associated transactivators.