The role of the histone H2A deubiquitinase MYSM1 in haematopoiesis and the immune response

• Antragsteller: Michael Förster, Ph.D.
• Fachliche Zuordnung: Immunologie
• Förderung: Förderung von 2013 bis 2015
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 237171680

Lymphocyte production and activation is regulated by complex programs of gene expression, and is essential for the normal functions of the immune system. Although many transcription factors involved in these pathways have been characterized, the functions of chromatin modifying proteins remain poorly understood. Recent work using novel transgenic mouse models, demonstrated that MYSM1-deficiency results in a severe defect in B and T cell development, and this phenotype is due to a cell intrinsic requirement for MYSM1. As MYSM1 is known to be a DNA-binding protein, a histone H2A deubiquitinase enzyme and an activator of gene expression, we hypothesize that this phenotype is due to a disruption of transcriptional programs during lymphocyte development. Given the fact that up to 10% of histone H2A is ubiquitinated across the genome of mammalian cells, and the broad expression of Mysm1 in haematopoietic and immune systems, we hypothesize that MYSM1 controls expression of many genes at different stages of lymphocyte development.The major aims of this project are therefore to characterize the functions of MYSM1 during lymphocyte development, lymphocyte activation and immune response. In order to define specific stages of B and T cell development that are critically dependent on MYSM1, we will use conditional mouse models enabling us to ablate MYSM1 expression during the pro-B cell stage and the mature-follicular stage of B cell development as well as the double-negative and the double-positive stages of thymocyte (T cell) differentiation. To provide a complete characterization of the transcriptional targets of MYSM1 in lymphoid cells we will carry out an in depth analysis of MYSM1 mediated DNA binding using chromatin immunoprecipitation (CHIP-Seq) experiments in both lymphoid cell lines and primary lymphocytes of transgenic mice. We will independently confirm our transcriptional target genes of MYSM1, by testing candidates for reduced gene expression in MYSM1-deficient mice, using primary lymphoid cells from mouse bone marrow or thymus. Lastly, we will aim to establish a role of Mysm1 in lymphocyte activation and immune response on both cellular and organismal levels with a combination of in vitro cell culture models assessing B and T cell activation after restimulation with monoclonal antibodies and other mitogenic stimuli as well as in vivo immunophenotyping in the murine system after immunization with T cell dependent and independent antigens.

• DFG-Verfahren: Forschungsstipendien
• Internationaler Bezug: Kanada
• Gastgeberin: Professorin Anastasia Nijnik, Ph.D.