"Oligodendrocytes (OL) are glial cells that mediate myelination of neurons, a process which is defective in multiple sclerosis (MS). Although OL precursors can initially promote remyelination in MS, this process eventually fails. OL precursors (OPCs) go through several epigenetic states during development and MS, which ultimately define their potential to differentiate and myelinate. Transcription factors such as Sox2, Sox10 and Sox9 are key regulators of OL development. However, it is unclear which are their transcriptional mechanisms of action and whether they recruit epigenetic modulators such as chromatin-modifying enzymes (ChMs). In this project, the main objectives are:1) COMPARATIVE QUANTITATIVE PROTEOMICS OF TRANSCRIPTION FACTOR COMPLEXESWe will generate a novel comprehensive library of OPCs representing different epigenetic states during OL development and animal models of MS. We will identify proteins that interact with the transcription factors Sox2, Sox9 and Sox10 in epigenetically distinct OPC populations using SILAC technology, coupled with antibody-based or biotin-based affinity purification strategies and Mass Spectrometry.2) IDENTIFICATION OF CHROMATIN SIGNATURES AND MOLECULAR MECHANISMS THAT DEFINE EPIGENETIC STATES AND CELL POTENTIAL IN OPCsTo determine if the expression/activity of the identified ChMs account for the variation on the differentiation potential of distinct OPCs, we will perform overexpression and RNAi-based screens. In order to assess how the enzymatic activities of the identified proteins modulate OL genes in different OPCs, we will investigate the genome-wide occupancy in OPCs of the identified chromatin-modifiers and associated histone modifications, by Chromatin Immunoprecipitation followed by Next Generation Sequencing.This project will introduce a new perspective into the study of OPC differentiation/myelination, by linking the epigenetic state of the cell with its potential during OL lineage specification and in MS."