Functional Char. of N-CoR/SMRT Corepressor Complexes in Adipocytes & Macrophages

点击翻译按钮获取中文摘要

The surprising relationship between macrophages and insulin resistance provides a promising interfacein which to applyour emerging understanding ofthe molecularmechanismsof nuclear receptor actions and recent progress in defining the underlying strategies oftransrepression. In Project 2, we will focus on NCoR/SMRT corepressor complexes as transcriptional checkpointscontrolling both ligand-dependent regulation ofgene expression by nuclear receptors and the activities of signal-dependent transcription factors that drive inflammatory programs of gene expression.We will better define the molecular mechanisms and roles ofthe TBLi,TBLRi and GPS2 componentsof N-CoR corepressor complexesin the regulation ofAPi/NF-kB target genes and we willuse genome-wide location analyses (GWLA) to investigate the roles ofthese proteins in positive and negative regulation of macrophage and adipocyte geneexpression. Three Specific Aims are proposed. Specific Aim i will test the hypothesis that N-CoR/SMRTcomplexes regulate inflammatory responses that contribute to insulin resistance and are targets ofanti-diabetic actions of PPARy agonists. These studies will be performed in collaboration with Units i and 3 using mice reconstituted with N-CoR'/'or SMRT/' fetal liver hematopoieticprogenitor cells. Specific Aim 2 will investigate the hypothesis that the TBLi/TBLRi exchangecomplexis regulated by signal-specific phosphorylation ofTBLRi/TBLi. We will investigate the protein kinase control of corepressorcomplex dismissal from AP-i and NF-kB target genes, and the role ofthese events in PPARy-mediated activationof positively regulated genes and transrepression ofinflammatory response genes. Specific Aim 3 will explore the role ofGPS2 and KIAAiySy in JNK-dependentgene activation/repression events and to test the hypothesis that GPS2is required for normal insulin sensitivity based on observations that JNK-expression and activityare consistently elevated in diet-induced obesity models and that AP-i activity is constitutively increased on a subset of genetargets in N-CoR"/' macrophages. These studies will utilize a combinationof single cell nuclear microinjectionof siRNAs, an ultra-sensitive, multiplexed RNAquantificationmethod (RASL) and ChlP-DASL to define roles of GPS2 in signal-dependent activation of inflammatory response genes.