Fig. 7.

UV light leads to an increase in transcriptional elongation. a Metagene analysis showing total RNA pol II occupancy measured by ChIP-seq in mock-treated U2OS cells and cells irradiated with UV light (40 J/m², 1 h recovery). All TSSs bound by RNA pol II in untreated cells and after UV light exposure were used for the analysis. Metagene analysis shows an average of two independent replicate ChIP-seq experiments. b Exposure of U2OS cells with UV light (40 J/m², 1 h recovery) promotes the release of RNA pol II into downstream regions of genes. The box plot shows the calculated RNA pol II release ratios (PRRs) in untreated cells and in cells irradiated with UV light. The average PRRs were calculated from two independent replicate experiments. The lower and upper hinges represent the first and third quartiles (25th and 75th percentiles, respectively). The line in the center of the box corresponds to the median of the data range. P-value was calculated using the Wilcoxon’s rank-sum test with continuity correction. c REACTOME terms significantly enriched among genes with UV light upregulated PRRs. The bar plot shows significantly overrepresented REACTOME terms associated with genes containing upregulated PRR compared with all RNA pol II bound genes. The significance of the enrichment of a specific term was determined using a hypergeometric test. P-values were corrected for multiple hypotheses testing using the Benjamini and Hochberg FDR. d UCSC Genome Browser tracks displaying the density of RNA pol II around the PLK3 and RPL11 gene in untreated cells and after exposure of cells with UV light. e Model for the NELF complex regulation by p38-MK2. Exposure of human cells to UV light leads to rapid activation of p38 and its downstream effector kinase MK2. MK2 triggers widespread phosphorylation of RNA-binding proteins, including the NELF complex subunit NELFE. Site-specific NELFE phosphorylation on S115 induces its transient interaction with 14-3-3. NELFE phosphorylation leads to dissociation of NELFE from chromatin that is accompanied by RNA pol II elongation