Role Of Histone Variants In Epigenetics Phenomena And Tumorigenesis
Reference : PhD Ali HAMICHE
Offer publication : April 5, 2016
Eukaryotic gene regulation, at the level of transcription, is connected to the structural organization of the genome. The basis for this structural organization is chromatin. Although it has been established that chromatin plays a fundamental role in maintaining regulated gene expression, very little is known about the chromatin structural and compositional changes that occur in early mammalian development when active and silenced chromosomal domains are established. The fundamental unit of chromatin, the nucleosome core, is a multi-subunit structure consisting of four different histone types H2A, H2B, H3 and H4. An important way to control chromatin function is to alter the biochemical make-up of the nucleosome by replacing an individual histone with a histone variant. There are at least six well-known histone variants (H3.3, CenpA, H2AX, H2ABbd,
H2AZ and macroH2A). Our laboratory is focusing on H3.3, H2AZ and macroH2A for their direct role in transcription regulation and oncogenesis. We have recently implicated macroH2A in PARP-1 enzymatic activity inactivation and transcription regulation (Ouararhni et al., 2006 Genes and Dev 20(23):3324-36). We have also discovered a new link between histone variants, transcription factors and chromatin remodeling factors (Drané et al., 2010 Genes Dev. 24(12):1253). This association with transcription factors and chromatin remodeling factors is novel and will certainly help us to understand how chromatin domains are established and how epigenetic information is stored and transmitted to daughter cells. Alteration of these
epigenetic marks is associated with developmental disorders and cancer.
The ongoing research in our laboratory aims at a better understanding of the role of histone variants and their associated proteins in maintaining regulated gene expression during development and cell differentiation.
The objective of this project is to analyze the role of the histone variant H2AZ and its deposition/exchange machineries in the epigenetic control of gene expression and genome integrity. We propose to study the biological function of H2AZ using a biochemical approach combined with mouse
knock in/knock out studies. We are particularly interested in the understanding of the role played by this variant in gene regulation, genome integrity, epigenetics phenomena and tumorigenesis. To learn how this variant contributes to gene expression and cancer, it is essential to: (i) determine its
location genome-wide, with both precision and completeness, (ii) to identify the mechanisms allowing its specific deposition at these locations, and (iii) to assess the dynamics and the stability of this deposition during the cell cycle. Such a systematic characterization of the dynamics of these epigenetic
marks should allow a better understanding of its functions, and will permit to interpret properly the genetic experiments designed to test these functions in vivo through loss or gain of function approaches directed towards both the variants and their deposition machineries. The selected candidate will participate in the identification and functional characterization of histone variant H2AZ assembly and deposition factors using biochemical techniques (cell fractionation and TAP-Tag purification). He or she will also identify genes directly regulated by H2AZ at a cellular level, by various molecular and cell biology approaches (ChIP, ChIP-sequencing, real time PCR, siRNA-based functional assays, reporter gene assays, confocal microscopy). Candidates must be highly motivated and have deep interests in chromatin and epigenetic regulations.
- WISHED SKILLS : Candidates should hold a Master's degree or equivalent. Background in either molecular biology, cell biology or biochemistry is required.
- EXPERTISES WHICH WILL BE ACQUIRED DURING THE TRAINING : We use tandem-affinity purification of large nuclear protein complexes to characterize the H2AZ-interactome. The student will reinforce molecular biology and basic biochemistry techniques that are routinely used in the lab and will also acquire a deep mastering of all techniques of molecular and cellular biology (cloning, PCR, immunocytochemistry, protein purification,
shRNA gene silencing, western-blot…), mouse genetics (knock-in, knock-out) and genomics (ChIP, ChIP seq, RNA seq).
Application Deadline : Dec. 31, 2016