18/03/2015 - 12:00 - Auditori PRBB

All you ever wanted to know about position effects in Drosophila cells but did not have the data to ask

Scientific sessions, CRG Group Leader Seminars

Guillaume Filion

Genome Architecture Group, Gene Regulation, Stem Cells and Cancer Programme, CRG

Short biography

Guillaume Filion started his doctoral research on epigenetics at the Curie Institute in 2004, under the supervision of Dr. PA Defossez. In 2008, he moved to the Netherlands, as a post-doc in the laboratory of Dr. B van Steensel. In 2012, he obtained a junior group leader position at the CRG.


Transcription factors (TFs) control gene expression by binding the promoter of the genes. However, this model does not account for position effects, which is a long standing observation that the locus of a gene influences its expression. We have developed a high throughput method called TRIP (Thousands of Reporters Inserted in Parallel) to integrate, map and measure the expression of reporter constructs. We have inserted 10 different reporters in Drosophila cells and we have collected a dataset of about 200,000 integrations, giving us unprecedented insight into how the organization of the genome shapes transcriptional landscapes. The integrated reporters define large domains of high and low activity. These domains are the same for all the reporters, but some promoters are more responsive to the context than others. Surprisingly, centromeric heterochromatin has a very distinct action depending on the promoter. Whereas some promoters are repressed upon landing in heterochromatin, others are activated. This difference of behavior corresponds to different architectures of the promoter, which suggests that promoters interpret the chromatin context in different ways to determine the level of transcription of a gene.