Invited by Benoit Palancade, Jérôme Déjardin (Biologie des séquences répétées, Institut de Génétique Humaine, CNRS-Université de Montpellier),will give a seminar entitled :
The control of DNA repeats in embryonic stem cells
Chromatin can be viewed as a highly complex mixture of proteins and nucleic acids that orchestrate DNA-based processes in the eukaryotic genome. Most of the mammalian genome is assembled into heterochromatin, a ‘closed’ structure imposed by several enzymatic activities. Such activities act on histones and the DNA itself to impinge on transcription, replication or repair.
Most of the heterochromatic fraction of the genome can be found at critical loci. These include telomeres, repetitive sequences around centromeres and a portion (about half) of the gene units encoding ribosomal RNAs. Defects in the regulation of these loci have therefore disastrous consequences on cell identity and can lead to developmental problems, cancer, premature aging or immune deficiencies. How precisely heterochromatic enzymes affect the composition of target loci has remained elusive and research in our laboratory primarily focuses on this question.
To understand how heterochromatin acts at the molecular level, we are looking at the effect of abrogating important heterochromatic activities, such as histone and/or DNA methyl-transferases, on the overall composition of key heterochromatic loci (telomeres, pericentromeres and rDNA).
Contact : benoit.palancade (at) ijm.fr