Project description:Genome-wide analysis of Prz1 in fission yeast reveals a novel inhibitory role in flocculation and a conserved activating role in cell wall organization [expression]
Project description:A new transcription factor for mitosis: In S. pombe, the RFX transcription factor Sak1 works with forkhead factors to regulate mitotic expression (array)
Project description:Genome-wide analysis of Prz1 in fission yeast reveals a novel inhibitory role in flocculation and a conserved activating role in cell wall organization [ChIP-chip]
Project description:A new transcription factor for mitosis: In S. pombe, the RFX transcription factor Sak1 works with forkhead factors to regulate mitotic expression (ChIP-Seq)
Project description:Folding of the mammalian genome is governed by architectural proteins, such asCTCF. TFIIIC, a RNA polymerase III transcription factor, has been identified as aninsulator but its role in genome topology is totally unknown. Here, we show that TFIIICestablishes long-range genomic interactions that affect gene expression. Upon serumstarvation (SS), TFIIIC occupancy increases at Alu elements (AEs) near promoters ofcell cycle-related genes. Bound AEs become H3K18 hyper-acetylated and fold tocontact distal pre-loaded CTCF sites near other cell cycle genes. The promoters ofthese genes also become hyper-acetylated ensuring their basal transcription during SSand their increased expression during serum re-exposure. Ablation of TFIIIC ordeletion of the TFIIIC-bound AE that loops to the G2/M cycling F (CCNF) locus affectsits expression and nuclear positioning. These results illustrate a novel function ofhuman TFIIIC in changing 3D genome topology through the epigenetic state of AEs.
Project description:Transcription factors (TFs) bind DNA in a sequence-specific manner and have been proven to serve as anchors to the 3D genome organization. These TFs are generally cell type-specific factor and/or developmental master regulators. General TFs (GTFs) which serve RNA polymerase recruitment to specific promoter sequences, however, can be part of very large protein complexes but their roles in genome architecture have not been carefully explored. Here, we used a bio-informatic approach of ChIP-seq and Hi-C data analysis to depict the role of one GTF of the RNA polymerase III system (TFIIIC) in several human cell lines, both normal and transformed. We find that TFIIIC occupancy within the genome mainly occurs at specific regions which largely correspond to Alu elements but also at characteristic classes of repetitive elements (REs) such as MIR, FLAMC and ALR/alpha, depending on the cell’s developmental origin. We then show that these TFIIIC-enriched regions are involved in cell type-specific DNA looping within the genome and do not depend on colocalization with the master architectural protein CTCF. This work extends previous knowledge about the role of TFIIIC as a bona fide genome organizer whose action can lead to cell type-dependent 3D genome looping via binding to REs.