Project description:Alu SINEs are the most numerous frequently occurring transcription units in our genomes and possess sequence competence for transcription by RNA Pol III. However, through poorly understood mechanisms, the Alu RNA levels are maintained at very low levels in normal somatic cells with obvious benefits of low rates of Alu retrotransposition and energy-economical deployment of RNA Pol III to the tRNA genes which share promoter structure and polymerase requirements with Alu SINEs. Using comparative ChIP sequencing, we unveil that a repeat binding protein, CGGBP1, binds to the transcriptional regulatory regions of Alu SINEs thereby impeding Alu transcription by inhibiting RNA Pol III recruitment. We show that this Alu-silencing depends on growth factor stimulation of cells and subsequent tyrosine phosphorylation of CGGBP1. Importantly, CGGBP1 ensures a sequence-specific discriminative inhibition of RNA Pol III activity at Alu promoters, while sparing the structurally similar tRNA promoters. Our data suggest that CGGBP1 contributes to growth-related transcription by preventing the hijacking of RNA Pol III by Alu SINEs. Examination of one DNA binding protein in two different conditions of treatment.
Project description:Using a massively parallel reporter assay (MPRA), we examined the effect of local sequence context on p53-dependent enhancer activity.
Project description:The activity of enhancers with dynamic P300 binding or mutagenized nuclear receptor motifs was assessed by massively parallel reporter assay during CM maturation.
Project description:Alu SINEs are the most numerous frequently occurring transcription units in our genomes and possess sequence competence for transcription by RNA Pol III. However, through poorly understood mechanisms, the Alu RNA levels are maintained at very low levels in normal somatic cells with obvious benefits of low rates of Alu retrotransposition and energy-economical deployment of RNA Pol III to the tRNA genes which share promoter structure and polymerase requirements with Alu SINEs. Using comparative ChIP sequencing, we unveil that a repeat binding protein, CGGBP1, binds to the transcriptional regulatory regions of Alu SINEs thereby impeding Alu transcription by inhibiting RNA Pol III recruitment. We show that this Alu-silencing depends on growth factor stimulation of cells and subsequent tyrosine phosphorylation of CGGBP1. Importantly, CGGBP1 ensures a sequence-specific discriminative inhibition of RNA Pol III activity at Alu promoters, while sparing the structurally similar tRNA promoters. Our data suggest that CGGBP1 contributes to growth-related transcription by preventing the hijacking of RNA Pol III by Alu SINEs.
Project description:We performed a massively parallel reporter assay on 2,396 genomic regions containing single nucleotide polymorphisms that are in high linkage disequilibrium with 97 lead variants from an obesity GWAS (PMID: 25673413). Regions were transfected into human SGBS preadipocytes, SGBS mature adipocytes, 3T3-L1 preadipocytes, HT22 hippocampal cells, and GT1-7 cells and assessed for enhancer activity. The processed file contains the MPRA barcodes.
