Integrated reporters reveal distinct pathways of
gene silencing in Drosophila

Guillaume Filion

Time: 5:20 - 6:00 PM

Type: Invited presentation

Affiliation: Centre of Genomic Regulation (CRG), Barcelona

Abstract

Recent genome-wide mapping studies in eukaryotes have shown that most transcriptionally silent domains lack repressive histone marks and repressors of transcription, prompting to ask what makes genes of these regions silent. Here we set out to answer this question by assaying position effects genome-wide for several reporters of transcription. To this end, we used a shotgun approach called TRIP (Thousands of Reporters Integrated in Parallel) to insert identical reporter genes at different loci of the Drosophila genome and measure their expression. We obtained expression data for more than 85,000 integrated reporters under eight different promoters, constituting the largest dataset of position effects available to date. We identified 10-100 kb domains of either high or low reporter activity. These domains are similar for different reporter constructs, showing that they correspond to the underlying organization of the genome. We identified novel protein signatures associated to the repression of reporter genes. One of them consists of chromatin proteins associated to transcriptionally active regions with a deficit of DMAP1, which suggests that this protein is critical for the expression of reporters. Overall, our results reveal that the effect of the chromatin context on transcription results from multiple processes at work simultaneously.