Promoter Nucleosome Disassembly from a Metazoan Model System A long-standing pursuit in modern biology is to understand how eukaryotic genes, tightly compacted into chromatin, are transformed into highly active transcription units. Due to the complexity of genome packaging and organization, we have a very limited understanding of the molecular mechanisms that control gene expression at the level of chromatin architecture. Central to the transformation of a silenced gene into a highly active transcription unit is the mobilization of nucleosomes. In recent years, a number of studies have established the existence of nucleosome-free regions within the promoters of eukaryotes genes. These regions represent a common """"""""signature"""""""" of transcriptionally active genes, where the degree of promoter DNA accessibility may directly correlate with gene activity. Unfortunately, little is known about the molecular steps involved in the formation of these regions, or the relevant proteins. We recently developed a biochemically-defined and biologically relevant model system for studying nucleosome disassembly using a human retroviral (HTLV-I) promoter. In this purely recombinant chromatin system, DNA-bound activators recruit the cellular coactivator p300 to the promoter. Following p300 recruitment, the histones become highly acetylated and the nucleosomes are disassembled from the promoter by the histone chaperone Nap1. Nucleosome disassembly is strictly acetyl-CoA dependent, uncoupled from transcription, and independent of ATP. These observations define a novel role for the acetyltransferase p300 and the histone chaperone Nap1 in the facilitation of acetylation-dependent nucleosome eviction. The Nyborg Project proposes to biochemically characterize nucleosome eviction with respect to histone acetylation, Nap1-mediated disassembly, and the impact of histone HI. Our studies will be enhanced by the highly complementary research proposed by our collaborators in the Luger and Stargell Projects, the efforts of our co-investigator Dr. Jeff Hansen, and the essential expertise and infrastructure provided by the Core facilities. This independent, yet highly interdependent, research effort will advance our understanding of the molecular mechanism underlying eukaryotic gene activation.
This proposal seeks to better understand the step-wise events required for the activation of genes in higher eukaryotes. Inappropriate gene expression is linked to a significant fraction of human disease states, including genetic disorders and cancer.
|Chen, Xu; D'Arcy, Sheena; Radebaugh, Catherine A et al. (2016) Histone Chaperone Nap1 Is a Major Regulator of Histone H2A-H2B Dynamics at the Inducible GAL Locus. Mol Cell Biol 36:1287-96|
|White, Alison E; Hieb, Aaron R; Luger, Karolin (2016) A quantitative investigation of linker histone interactions with nucleosomes and chromatin. Sci Rep 6:19122|
|Chatterjee, Nilanjana; North, Justin A; Dechassa, Mekonnen Lemma et al. (2015) Histone Acetylation near the Nucleosome Dyad Axis Enhances Nucleosome Disassembly by RSC and SWI/SNF. Mol Cell Biol 35:4083-92|
|Brehove, Matthew; Wang, Tao; North, Justin et al. (2015) Histone core phosphorylation regulates DNA accessibility. J Biol Chem 290:22612-21|
|Kuo, Yin-Ming; Henry, Ryan A; Huang, Liangqun et al. (2015) Utilizing targeted mass spectrometry to demonstrate Asf1-dependent increases in residue specificity for Rtt109-Vps75 mediated histone acetylation. PLoS One 10:e0118516|
|Mattiroli, Francesca; D'Arcy, Sheena; Luger, Karolin (2015) The right place at the right time: chaperoning core histone variants. EMBO Rep 16:1454-66|
|Groocock, Lynda M; Nie, Minghua; Prudden, John et al. (2014) RNF4 interacts with both SUMO and nucleosomes to promote the DNA damage response. EMBO Rep 15:601-8|
|Muthurajan, Uma M; Hepler, Maggie R D; Hieb, Aaron R et al. (2014) Automodification switches PARP-1 function from chromatin architectural protein to histone chaperone. Proc Natl Acad Sci U S A 111:12752-7|
|Blakeslee, Weston W; Wysoczynski, Christina L; Fritz, Kristofer S et al. (2014) Class I HDAC inhibition stimulates cardiac protein SUMOylation through a post-translational mechanism. Cell Signal 26:2912-20|
|Chodaparambil, Jayanth V; Pate, Kira T; Hepler, Margretta R D et al. (2014) Molecular functions of the TLE tetramerization domain in Wnt target gene repression. EMBO J 33:719-31|
Showing the most recent 10 out of 32 publications