Bio

Academic Appointments


Honors & Awards


  • Terman Fellow Award, Hewlett Foundation (2010-2013)
  • Kimmel Scholar Award, Sidney Kimmel Foundation for Cancer Research (2010-2012)
  • Pathways to Independence Award (K99/R00), NIH (2009-2012)

Professional Education


  • Ph.D., Baylor College of Medicine, Biomedical Sciences (2004)

Research & Scholarship

Current Research and Scholarly Interests


Our research interests are to elucidate the contribution of chromatin to mechanisms that promote genomic integrity. The regulation of chromatin is a crucial component of DNA metabolism and processing in eukaryotic organisms. Chromatin-remodeling complexes, modified histones, and higher order chromatin structure are all factors influencing genome stability. We utilize an integrated approach of genetic, biochemical, and molecular techniques, in both yeast and mammalian systems, to examine the involvement of chromatin in processes that prevent genome instability and the pathogenesis of disease.

Teaching

2013-14 Courses


Postdoctoral Advisees


Graduate and Fellowship Programs


Publications

Journal Articles


  • New marks on the block Set5 methylates H4 lysines 5, 8 and 12 NUCLEUS-AUSTIN Green, E. M., Morrison, A. J., Gozani, O. 2012; 3 (4): 335-339

    Abstract

    The methylation of lysine residues in the N-terminal tails of histones is a highly conserved mechanism that regulates critical functions of chromatin, such as the control of gene expression. Using a biochemical approach, we recently identified new methylation marks on the histone H4 tail in budding yeast at lysines 5, 8 and 12, catalyzed by the previously-uncharacterized enzyme Set5. Genetic studies revealed that Set5 functions in cellular processes that also rely on the global chromatin modifying complexes COMPASS and NuA4, which methylate H3 lysine 4 and acetylate H4 lysines 5, 8 and 12, respectively. The identification of new methylation events on the H4 tail raises many intriguing questions regarding their function and their interaction with known histone modifications. Here, we analyze the insights gained about the new enzyme Set5 and the implications for new functionality added to the H4 tail.

    View details for DOI 10.4161/nucl.20695

    View details for Web of Science ID 000315929000009

    View details for PubMedID 22688645

  • Chromatin remodelling beyond transcription: the INO80 and SWR1 complexes NATURE REVIEWS MOLECULAR CELL BIOLOGY Morrison, A. J., Shen, X. 2009; 10 (6): 373-384

    Abstract

    Chromatin-modifying factors have essential roles in DNA processing pathways that dictate cellular functions. The ability of chromatin modifiers, including the INO80 and SWR1 chromatin-remodelling complexes, to regulate transcriptional processes is well established. However, recent studies reveal that the INO80 and SWR1 complexes have crucial functions in many other essential processes, including DNA repair, checkpoint regulation, DNA replication, telomere maintenance and chromosome segregation. During these diverse nuclear processes, the INO80 and SWR1 complexes function cooperatively with their histone substrates, gamma-H2AX and H2AZ. This research reveals that INO80 and SWR1 ATP-dependent chromatin remodelling is an integral component of pathways that maintain genomic integrity.

    View details for DOI 10.1038/nrm2693

    View details for Web of Science ID 000266270900012

    View details for PubMedID 19424290

  • Mec1/Tel1 phosphorylation of the INO80 Chromatin Remodeling Complex Influences DNA damage checkpoint responses CELL Morrison, A. J., Kim, J., Person, M. D., Highland, J., Xiao, J., Wehr, T. S., Hensley, S., Bao, Y., Shen, J., Collins, S. R., Weissman, J. S., Delrow, J., Krogan, N. J., Haber, J. E., Shen, X. 2007; 130 (3): 499-511

    Abstract

    The yeast Mec1/Tel1 kinases, ATM/ATR in mammals, coordinate the DNA damage response by phosphorylating proteins involved in DNA repair and checkpoint pathways. Recently, ATP-dependent chromatin remodeling complexes, such as the INO80 complex, have also been implicated in DNA damage responses, although regulatory mechanisms that direct their function remain unknown. Here, we show that the Ies4 subunit of the INO80 complex is phosphorylated by the Mec1/Tel1 kinases during exposure to DNA-damaging agents. Mutation of Ies4's phosphorylation sites does not significantly affect DNA repair processes, but does influence DNA damage checkpoint responses. Additionally, ies4 phosphorylation mutants are linked to the function of checkpoint regulators, such as the replication checkpoint factors Tof1 and Rad53. These findings establish a chromatin remodeling complex as a functional component in the Mec1/Tel1 DNA damage signaling pathway that modulates checkpoint responses and suggest that posttranslational modification of chromatin remodeling complexes regulates their involvement in distinct processes.

    View details for DOI 10.1016/j.cell.2007.06.010

    View details for Web of Science ID 000249038100017

    View details for PubMedID 17693258

  • INO80 and gamma-H2AX interaction links ATP-dependent chromatin remodeling to DNA damage repair CELL Morrison, A. J., Highland, J., Krogan, N. J., Arbel-Eden, A., Greenblatt, J. F., Haber, J. E., Shen, X. T. 2004; 119 (6): 767-775

    Abstract

    While the role of ATP-dependent chromatin remodeling in transcription is well established, a link between chromatin remodeling and DNA repair has remained elusive. We have found that the evolutionarily conserved INO80 chromatin remodeling complex directly participates in the repair of a double-strand break (DSB) in yeast. The INO80 complex is recruited to a HO endonuclease-induced DSB through a specific interaction with the DNA damage-induced phosphorylated histone H2A (gamma-H2AX). This interaction requires Nhp10, an HMG-like subunit of the INO80 complex. The loss of Nhp10 or gamma-H2AX results in reduced INO80 recruitment to the DSB. Finally, components of the INO80 complex show synthetic genetic interactions with the RAD52 DNA repair pathway, the main pathway for DSB repair in yeast. Our findings reveal a new role of ATP-dependent chromatin remodeling in nuclear processes and suggest that an ATP-dependent chromatin remodeling complex can read a DNA repair histone code.

    View details for Web of Science ID 000225907200008

    View details for PubMedID 15607974

  • Rb targets histone H3 methylation and HP1 to promoters NATURE Nielsen, S. J., Schneider, R., Bauer, U. M., Bannister, A. J., Morrison, A., O'Carroll, D., Firestein, R., Cleary, M., Jenuwein, T., Herrera, R. E., Kouzarides, T. 2001; 412 (6846): 561-565

    Abstract

    In eukaryotic cells the histone methylase SUV39H1 and the methyl-lysine binding protein HP1 functionally interact to repress transcription at heterochromatic sites. Lysine 9 of histone H3 is methylated by SUV39H1 (ref. 2), creating a binding site for the chromo domain of HP1 (refs 3, 4). Here we show that SUV39H1 and HP1 are both involved in the repressive functions of the retinoblastoma (Rb) protein. Rb associates with SUV39H1 and HP1 in vivo by means of its pocket domain. SUV39H1 cooperates with Rb to repress the cyclin E promoter, and in fibroblasts that are disrupted for SUV39, the activity of the cyclin E and cyclin A2 genes are specifically elevated. Chromatin immunoprecipitations show that Rb is necessary to direct methylation of histone H3, and is necessary for binding of HP1 to the cyclin E promoter. These results indicate that the SUV39H1-HP1 complex is not only involved in heterochromatic silencing but also has a role in repression of euchromatic genes by Rb and perhaps other co-repressor proteins.

    View details for Web of Science ID 000170202900051

    View details for PubMedID 11484059

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