The histone code hypothesis proposes that cell fate decisions are achieved through creation of stable epigenetic histone marks at gene loci. These marks can be localized to promoters and transcribed regions of genes or can extend many kilobases beyond these boundaries. Although it is well established that certain histone marks are associated with transcriptional activation and other histone marks are associated with transcriptional repression, the precise mechanisms by which histone marks activate or repress transcription is incompletely understood. Further, it is becoming increasingly apparent that both activating and repressive marks are formed at loci of developmentally regulated genes and it is thought that these dual marks ensure developmental plasticity. For example, the Ifng gene exhibits complex activating and repressive patterns of epigenetic modifications that cover a region spanning over 50 kb of upstream and downstream genomic DNA in cells that express or silence Ifng. Given the critical role epigenetic marks play in normal development, it is becoming increasingly apparent that epigenetic defects also contribute to disease processes, including autoimmunity. Our results also demonstrate that failure to properly establish this long-range histone code may contribute to the characteristic over-production of IFN-3 by proliferating T cells from mice that develop autoimmune diabetes. To investigate these questions, we plan a three-pronged approach. First, we will prepare and analyze functional properties of transgenic mice with a wild-type human bacterial artificial chromosome (BAC) containing the IFNG gene and approximately 100 kb of flanking upstream and downstream sequence and BAC transgenic mice with various large (20-40 kb) and small (1kb) deletions within the 200 kb BAC. Second, we will perform detailed structure-function and nuclear positioning analyses to identify genomic sequences critical for these essential processes. Third, we will use several approaches to manipulate the formation stable long-range epigenetic histone marks across the IFNG locus and evaluate alterations in transcription, chromosomal conformation and nuclear positioning of the IFNG locus. Together, these studies will provide direct links between the function of the genetic code and the epigenetic code. They will also identify defects in the epigenetic code that may contribute to autoimmune disease.

Public Health Relevance

The histone code hypothesis proposes that cell fate decisions are achieved through creation of stable epigenetic histone marks at gene loci. In this proposal, we plan to elucidate mechanisms underlying formation of long range histone marks across the Ifng locus in developing effector Th1 and Th2 cells and functional consequences created by these marks. Increasing evidence suggests that imbalance in the histone code may contribute to disease onset or pathogenesis, including autoimmune diseases, and it may be possible to affect the course of disease by altering the epigenetic code through increasing levels of activating histone acetylation marks or decreasing levels of inhibitory histone methylation marks, either generally or at specific genomic loci.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
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Cellular and Molecular Immunology - A Study Section (CMIA)
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Miller, Lara R
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Vanderbilt University Medical Center
Internal Medicine/Medicine
Schools of Medicine
United States
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Zhang, Fanglin; Tossberg, John T; Spurlock, Charles F et al. (2014) Expression of IL-33 and its epigenetic regulation in Multiple Sclerosis. Ann Clin Transl Neurol 1:307-318
Collier, Sarah P; Henderson, Melodie A; Tossberg, John T et al. (2014) Regulation of the Th1 genomic locus from Ifng through Tmevpg1 by T-bet. J Immunol 193:3959-65
Spurlock 3rd, Charles F; Tossberg, John T; Matlock, Brittany K et al. (2014) Methotrexate inhibits NF-?B activity via long intergenic (noncoding) RNA-p21 induction. Arthritis Rheumatol 66:2947-57
Aune, Thomas M; Collins, Patrick L; Collier, Sarah P et al. (2013) Epigenetic Activation and Silencing of the Gene that Encodes IFN-?. Front Immunol 4:112
Tossberg, John T; Crooke, Philip S; Henderson, Melodie A et al. (2013) Using biomarkers to predict progression from clinically isolated syndrome to multiple sclerosis. J Clin Bioinforma 3:18
Fites, J Scott; Ramsey, Jeremy P; Holden, Whitney M et al. (2013) The invasive chytrid fungus of amphibians paralyzes lymphocyte responses. Science 342:366-9
Spurlock 3rd, Charles F; Tossberg, John T; Fuchs, Howard A et al. (2012) Methotrexate increases expression of cell cycle checkpoint genes via JNK activation. Arthritis Rheum 64:1780-9
Spurlock 3rd, Charles F; Aune, Zachary T; Tossberg, John T et al. (2011) Increased sensitivity to apoptosis induced by methotrexate is mediated by JNK. Arthritis Rheum 63:2606-16
Wang, Lily; Jia, Peilin; Wolfinger, Russell D et al. (2011) An efficient hierarchical generalized linear mixed model for pathway analysis of genome-wide association studies. Bioinformatics 27:686-92
Aune, Thomas M; Collins, Patrick L; Chang, Shaojing (2009) Epigenetics and T helper 1 differentiation. Immunology 126:299-305

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