The long-term goal of the research in this proposal is to gain a molecular understanding of chromatin regulation by histone modification with the small ubiquitin-like modifier (SUMO) protein. The post-translational modification (PTM) of histone proteins by a range of chemical groups is observed in all eukaryotes. An extensive body of work has established that the dynamic regulation of histone PTMs and the biochemical relationships between specific PTMs underlie critical processes such as DNA transcription, repair, and replication. One dramatic PTM, the conjugation of histone lysine side-chains with the protein SUMO (termed SUMOylation) occurs widely, from yeast to humans, and is implicated in transcriptional silencing and DNA double-strand break repair. The dysregulation of these critical processes by environmental or genetic factors is linked to many human diseases such as cancers of the blood, brain, breast, and kidneys, to name a few. Therefore elucidating the molecular mechanisms by which histone SUMOylation regulates transcription and gene repair are essential first steps toward devising rational therapeutic strategies for acute human diseases. The biophysical and biochemical characterization of SUMOylated chromatin has until recently been limited by the inability to obtain sufficient quantities of homogeneously SUMOylated histones for in vitro studies, either from cultured cells or by enzymatic means. Hence, essentially nothing is known about the direct and/or indirect mechanisms by which histone SUMOylation influences the structure and function of human chromatin. In order to address this significant gap in our knowledge, we aim to combine the tools of synthetic organic chemistry, biochemistry, molecular and cell biology. Our chemical biology-based approach involves synthesizing site-specifically SUMOylated histones for biochemical and biophysical studies, as well as generating antibodies to investigate the genome-wide occurrence of SUMOylated histones. By adopting methods to study histone SUMOylation both in vitro and in cells, we will gain a comprehensive understanding of the mechanistic roles for this modification in normal growth and in disease progression. The specific research objectives of this proposal are: (1) To elucidate the direct effects of SUMOylation on chromatin structure and stability. (2) To elucidate the biochemical relationship between histone SUMOylation and gene-activating histone modifications, and (3) To investigate the histone SUMOylation state of active and silent regions of human chromatin. The successful completion of these aims will lead to a molecular understanding of SUMO-mediated changes in chromatin structure and function. Identifying new protein- protein interactions in regulatory pathways involving SUMOylated histones may provide new targets for therapeutic invention in diseases arising from the dysregulation of histone modifications. Finally, the methodologies described in this proposal are broadly applicable and will serve as transformative tools for studying SUMO-mediated processes in the context of other key signaling proteins, such as transcription factors, DNA- and histone-modifying enzymes.
Chromatin is the massive complex of DNA and protein that forms chromosomes within the nuclei of our cells. Environmental and genetic factors that change the structure and function of chromatin interfere with the regulation and repair of our genes and lead to diseases such as cancer, cardiac hypertrophy, and fragile X syndrome. The long-term goal of our research program is to gain a molecular understanding of the biophysical and biochemical mechanisms underlying chromatin regulation by chemical modifications of the histone protein component of chromatin. The specific focus of this proposal is to understand the effect of histone modification by the small ubiquitin-like modifier (SUMOylation) on the structure of chromatin and to identify the biochemical relationships between SUMOylation and histone modifications that are known to be dysregulated in human diseases.
|Dhall, Abhinav; Weller, Caroline E; Chu, Aurea et al. (2017) Chemically Sumoylated Histone H4 Stimulates Intranucleosomal Demethylation by the LSD1-CoREST Complex. ACS Chem Biol 12:2275-2280|
|Shelton, Patrick M M; Weller, Caroline E; Chatterjee, Champak (2017) A Facile N-Mercaptoethoxyglycinamide (MEGA) Linker Approach to Peptide Thioesterification and Cyclization. J Am Chem Soc 139:3946-3949|
|Sivanesam, Kalkena; Kier, Brandon L; Whedon, Samuel D et al. (2016) Hairpin structure stability plays a role in the activity of two antimicrobial peptides. FEBS Lett 590:4480-4488|
|Weller, Caroline E; Dhall, Abhinav; Ding, Feizhi et al. (2016) Aromatic thiol-mediated cleavage of N-O bonds enables chemical ubiquitylation of folded proteins. Nat Commun 7:12979|
|Whedon, Samuel D; Markandeya, Nagula; Rana, Ambar S J B et al. (2016) Selenocysteine as a latent bioorthogonal electrophilic probe for deubiquitylating enzymes. J Am Chem Soc :|
|Dhall, A; Weller, C E; Chatterjee, C (2016) Rapid Semisynthesis of Acetylated and Sumoylated Histone Analogs. Methods Enzymol 574:149-165|
|Li, Heng; Lim, Kah Suan; Kim, Hyungjin et al. (2016) Allosteric Activation of Ubiquitin-Specific Proteases by ?-Propeller Proteins UAF1 and WDR20. Mol Cell 63:249-260|
|Jastrab, Jordan B; Wang, Tong; Murphy, J Patrick et al. (2015) An adenosine triphosphate-independent proteasome activator contributes to the virulence of Mycobacterium tuberculosis. Proc Natl Acad Sci U S A 112:E1763-72|
|Eustis, Ian C; Huang, Jessica; Pilkerton, Meagan E et al. (2015) A time-resolved Förster resonance energy transfer assay to measure activity of the deamidase of the prokaryotic ubiquitin-like protein. Anal Biochem 487:27-9|
|Weller, Caroline E; Chatterjee, Champak (2015) All about that Amide Bond: The Sixth Chemical Protein Synthesis (CPS) Meeting. Chembiochem 16:2531-6|
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