dr. Remus Dame: Fine-tuning the structural organization of prokaryotic genomes
|When:||Th 22-01-2015 11:00 - 12:00|
Loop formation is key to the global organization of genomes in organisms from all three domains of life. Genomes are organized dynamically and their re-modelling is implied in translating external signals into transcription of specific genes. The bacterial chromatin protein H-NS and the archaeal chromatin protein Alba are capable of forming bridges between DNA segments in vitro and thus candidates for genomic loop formation in vivo. H-NS is a global regulator of transcription and a similar role has been suggested for Alba. We investigate how the DNA bridging activity of these proteins is fine-tuned by physico-chemical conditions and interaction with other proteins. We use a multi-disciplinary approach to address this question in vitro and in vivo, employing tools from biophysics, biochemistry, chemical biology and genetics. We demonstrate that for both proteins there is a delicate balance between two binding modes (stiffening and bridging), which can be shifted when conditions are changed or interaction partners are present. Our observations yield models for fine-tuning of genome organization and for the translation of changes in genome organization into transcriptional activity.