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Mary Bryk

Bryk, Mary
Mary Bryk
Associate Professor
BioBio / Room 334A
Undergraduate Education
B.Sc. Cornell University (1985)
Graduate Education
M.S. Albany Medical College (1991)
Ph.D. Albany Medical College (1994)
Postdoc. Wadsworth Center, Albany (1995-1997)
Harvard Medical School, Boston (1997-2002)
Joined Texas A&M in 2002

Transcriptional Silencing/Chromatin Structure

How cells regulate gene expression is fundamental to most aspects of biology. Research in our laboratory focuses on understanding how gene expression is regulated in inactive or transcriptionally silenced regions of a genome. Our experiments are performed in the yeast Saccharomyces cerevisiae. We identify proteins that regulate transcriptional silencing using classical and modern genetic techniques. Then we investigate how these factors contribute to transcriptional silencing using a combination of genetic, molecular, and biochemical methods.

Our studies focus on silencing of genes inserted in the ribosomal DNA (rDNA) locus. In our early studies, we found that yeast retrotransposons, known as Ty1 elements, are silenced when they integrate into the rDNA locus. Thus, we use genetically marked Ty1 elements, as well as more traditional marker genes, to identify and characterize proteins that regulate transcriptional silencing in the rDNA.

Research from our lab and others has identified several proteins that regulate transcriptional silencing through effects on chromatin structure. These proteins include histones, rDNA-binding proteins and histone-modifying enzymes. Some of these proteins also influence gene expression at other silenced regions of the yeast genome. The chromatin structure of the rDNA is not only important for maintaining transcriptional silencing but also for repressing genetic recombination. Alterations in the level of recombination at the rDNA can decrease the stability of the locus and may lead to premature aging and death.

The goal of our lab is to learn more about the ways that cells regulate transcriptional silencing. Our findings will increase our understanding of how chromatin dynamics influence gene expression and how cells maintain the integrity of their genome. Many of the factors we study have homologues in human cells indicating that our discoveries may provide insight into mechanisms that regulate gene expression in higher eukaryotes.



Recent Publications

  1. Williamson, K, Schneider, V, Jordan, RA, Mueller, JE, Henderson Pozzi, M, Bryk, M et al.. Catalytic and functional roles of conserved amino acids in the SET domain of the S. cerevisiae lysine methyltransferase Set1. PLoS ONE. 2013;8 (3):e57974.
    doi: 10.1371/journal.pone.0057974. PubMed PMID:23469257. PubMed Central PMC3585878.

  2. Blank, HM, Li, C, Mueller, JE, Bogomolnaya, LM, Bryk, M, Polymenis, M et al.. An increase in mitochondrial DNA promotes nuclear DNA replication in yeast. PLoS Genet. 2008;4 (4):e1000047.
    doi: 10.1371/journal.pgen.1000047. PubMed PMID:18404213. PubMed Central PMC2289842.

  3. Li, C, Mueller, JE, Elfline, M, Bryk, M. Linker histone H1 represses recombination at the ribosomal DNA locus in the budding yeast Saccharomyces cerevisiae. Mol. Microbiol. 2008;67 (4):906-19.
    doi: 10.1111/j.1365-2958.2007.06101.x. PubMed PMID:18179596. .

  4. Mueller, JE, Li, C, Bryk, M. Isw2 regulates gene silencing at the ribosomal DNA locus in Saccharomyces cerevisiae. Biochem. Biophys. Res. Commun. 2007;361 (4):1017-21.
    doi: 10.1016/j.bbrc.2007.07.140. PubMed PMID:17689493. PubMed Central PMC2083704.

  5. Mueller, JE, Bryk, M. Isw1 acts independently of the Isw1a and Isw1b complexes in regulating transcriptional silencing at the ribosomal DNA locus in Saccharomyces cerevisiae. J. Mol. Biol. 2007;371 (1):1-10.
    doi: 10.1016/j.jmb.2007.04.089. PubMed PMID:17561109. PubMed Central PMC1995125.

  6. Li, C, Mueller, JE, Bryk, M. Sir2 represses endogenous polymerase II transcription units in the ribosomal DNA nontranscribed spacer. Mol. Biol. Cell. 2006;17 (9):3848-59.
    doi: 10.1091/mbc.E06-03-0205. PubMed PMID:16807355. PubMed Central PMC1593162.

  7. Mueller, JE, Canze, M, Bryk, M. The requirements for COMPASS and Paf1 in transcriptional silencing and methylation of histone H3 in Saccharomyces cerevisiae. Genetics. 2006;173 (2):557-67.
    doi: 10.1534/genetics.106.055400. PubMed PMID:16582434. PubMed Central PMC1526511.

  8. Bryk, M, Briggs, SD, Strahl, BD, Curcio, MJ, Allis, CD, Winston, F et al.. Evidence that Set1, a factor required for methylation of histone H3, regulates rDNA silencing in S. cerevisiae by a Sir2-independent mechanism. Curr. Biol. 2002;12 (2):165-70.
    . PubMed PMID:11818070. .

  9. Briggs, SD, Bryk, M, Strahl, BD, Cheung, WL, Davie, JK, Dent, SY et al.. Histone H3 lysine 4 methylation is mediated by Set1 and required for cell growth and rDNA silencing in Saccharomyces cerevisiae. Genes Dev. 2001;15 (24):3286-95.
    doi: 10.1101/gad.940201. PubMed PMID:11751634. PubMed Central PMC312847.

  10. Bryk, M, Banerjee, M, Conte, D Jr, Curcio, MJ. The Sgs1 helicase of Saccharomyces cerevisiae inhibits retrotransposition of Ty1 multimeric arrays. Mol. Cell. Biol. 2001;21 (16):5374-88.
    doi: 10.1128/MCB.21.16.5374-5388.2001. PubMed PMID:11463820. PubMed Central PMC87260.

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