Purdue University PURDUE AGRICULTURE
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Scott D Briggs

Associate Professor of Biochemistry

Department: Biochemistry
Phone: 765.494.0112
Fax: 765.494.7897
Office: BCHM B10
E-mail: sdbriggs@purdue.edu

Area of Expertise: Role of histone methylation in gene expression and oncogenesis
Curriculum Vitae

 

In the eukaryotic cell, DNA is associated with protein factors to form chromatin.  The fundamental repeating unit of chromatin is called the nucleosome where 146 base pairs of DNA is wrapped around two copies of each histone protein (H3, H4, H2A, and H2B).  An important role for histone proteins is to help in the compaction of our genome into the nucleus of the cell.  However, this compaction of DNA can restrict nuclear factors from gaining access to the DNA template.  Therefore, this inherently restrictive environment must be regulated and organized to allow permissive cellular processes such as gene transcription, replication, recombination, repair and chromosomal segregation.  The mechanisms that regulate chromatin structure and function are histone modifying complexes that posttranslationally modify histones.  Generally, all of the histone modifications have been located on the N- and C-terminal tail domains.  However, recent evidence has indicated novel modification sites within the central part of the histone called the histone fold-domain. Since posttranslational modifications on histones such as acetylation, phosphorylation, ubiquitination, and/or methylation can influence the chromatin environment and gene expression, we are interested in studying the machinery that mediates these modifications and how mis-regulation of these enzymes can lead to a disease state.

 

Posttranslational modifications on histones.  Specific amino acid sites of posttranslational modifications (acetylation, phosphorylation, ubiquitination and methylation) that are known to occur on histones are indicated by colored symbols. Half of the structure of the nucleosome core particle H3 (yellow), H4 (blue), H2A (red) and H2B (green) are shown in color.  The other half is represented in grey

Histone methylation and regulation

Work on histone methylation has lead to the identification of histone methylation sites and their corresponding methyltransferases.  Histone methylation has now been identified on lysine (Lys) and arginine (Arg) residues on histone H3 and H4 (see figure).  The catalytic core for some but not all lysine histone methyltransferases (HMTs) resides in the SET domain.  A conserved domain named for its appearance in Su(var) 3-9 (suppressor of position effect variegation), E(z) (enhancer of zeste), and Trx (trithorax).  In contrast to lysine HMTs, arginine HMTs do not contain a SET domain but have highly conserved non-contiguous amino acid residues that are essential for forming its catalytic core.  Histone lysine methylation is a unique posttranslational modification since it can exist in three different methyl states (mono-, di- and trimethyl).  In S. cerevisiae, all three methylation states are catalyzed by the same enzyme.  For example, Set1, Set2 and Dot1 are responsible for catalyzing mono-, di- and trimethylation on histone H3 at Lys4, Lys36, and Lys79, respectively.  Interestingly, histone methylation can organize chromatin into an active or repressed state depending on the site of methylation and methyl-binding protein.  My lab has largely exploited the strengths of yeast and mammalian model organisms in combination with biochemistry and molecular biology techniques.  We are currently using budding yeast as a model system to understand how Set1, Set2 and Dot1 methyltransferases and their sites of histone modification function. 

Methyltransferases and cancer

Several histone methyltransferases and demethylases are found either mutated, chromosomal translocated, or over-expressed when isolated from oncogenic cells suggesting that they play an important regulatory role in the cell.  Therefore, we are interested in determining how mis-regulation and/or aberrant expression of these methyltransferases can lead to an oncogenic event and how aberrant histone methylation may play a role in oncogenesis.  Therefore, understanding the mechanism of how histone methyltransferases and demethylases function will provide key insights into designing small molecule inhibitors for potential novel chemotherapeutic drugs.

 

 

- Recent Publications

South, P. F., Harmeyer, K. M., Serratore, N. D., & Briggs, S. D. (2013). H3K4 methyltransferase Set1 is involved in maintenance of ergosterol homeostasis and resistance to Brefeldin A. Proc. Natl. Acad. Sci. U.S.A., 11, E1016-E1025. Retrieved from http://www.pnas.org/cgi/pmidlookup?view=long&pmid=23382196

Mersman, D. P., Du, H. N., Fingerman, I. M., South, S. D., & Briggs, S. D. (2012). Charge-based interaction conserved within hisone H3 lysine 4 (H3K4) methyltransferase complexes is needed for protein stability, histone methylation, and gene expression. J. Biol. Chem., 287, 2652-2665. Retrieved from http://www.jbc.org/content/287/4/2652.full.pdf+html

Du, H. N., & Briggs, S. D. (2010). A nucleosome surface formed by histone H4, H2A, and H3 residues is needed for proper histone H3 Lys36 methylation, histone acetylation, and repression of cryptic transcription. J. Biol. Chem., 285, 11704-11713. Retrieved from http://www.jbc.org/content/285/15/11704.full.pdf+html

South, P. F., Fingerman, I. M., Mersman, D. P., Du, H. N., & Briggs, S. D. (2010). A conserved interaction between the SDI domain of Bre2 and the Dpy-3- Domain of Sdc1 is required for histone methylation and gene expression. J. Biol. Chem., 285(1), 595-607. Retrieved from http://www.jbc.org/content/285/1/595.full.pdf+html

Plazas-Mayorca, M. D., Zee, B. M., Young, N. L., Fingerman, I. M., LeRoy, G., Briggs, S. D., & Garcia, B. A. (2009). One-pot shotgun quantitative mass spectrometry characterization of histones. J. Proteome Res., 8(11), 5367-5374.

Mersman, D. P., Harmeyer, K. M., & Briggs, S. D. (2009). To be or not to be demethylated. Cell Cycle, 8, 2135-2137.

Mersman, D. P., Du, H. N., Fingerman, I. M., South, P. F., & Briggs, S. D. (2009). Polyubiquitination of the demethylase Jhd2 controls histone methylation and gene expression. Genes & Development, 23(8), 951-962.

Fingerman, I. M., Du, H., & Briggs, S. D. (2008). Controlling histone methylation via trans-histone pathways. Epigenetics, 3(5), 237-242.

Du, H., Fingerman, I., & Briggs, S. D. (2008). Histone H3 K36 methylation is mediated by a trans-histone methylation pathway involving an involing. Genes & Development, 22(20), 2786-2798.

Fingerman, I. M., Li, H. C., & Briggs, S. D. (2007). A charge-based interaction between histone H4 and Dot1 is required for H3K79 methylation and telomere silencing: Identification of a new trans-histone pathway. Genes and Development, 21, 2018-2029.

 

+ Patents

 

- Awards & Honors

Kohls Outstanding Undergraduate Teacher Award for Biochemistry (2012). Purdue University Department of Biochemistry.

Faculty Scholar (2011). Purdue University.

Faculty Scholar (2010). Purdue University.

Seed for Success (2006). Purdue University.

Fellowship (2004). Leukemia and Lymphoma Society.

Sidney Kimmel Scholar (2004). Sidney Kimmel Foundation.

Walther Assistant Professor of Biochemistry (2004). Walther Cancer Institute.

 

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