Dr Dermot Walls

Biography

Dermot Walls is an Associate Professor at Dublin City University.

He graduated with a BSc (Hons) in Microbiology (1984) and later a PhD in Molecular Biology/Virology (1988) from the National University of Ireland, Galway. He previously worked at the Institut Gustave Roussy (Oncogenic Virus Laboratory CNRS URA 1301) in Paris, France, where he held fellowships from the European Molecular Biology Organisation (EMBO), the Association pour la Recherche sur le Cancer (ARC) and the Centre National de la Recherche Scientifique (CNRS). He spent 2005-2006 on sabbatical leave at the Kimmel Comprehensive Cancer Center (Viral Oncology Programme) in Johns Hopkins University, Baltimore (MD., USA).

Research Expertise

PhD Students

  • PhD Student #1
  • PhD Student #2
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Select Publications

Manipulation of the toll-like receptor 7 signaling pathway by Epstein-Barr virus
  Silva ER, Cooney G, Hamley IW, Alves WA, Lee S, O'Connor BF, Reza M, Ruokolainen J, Walls D.HJ Martin, JM Lee, D Walls, SD Hayward      2007      Journal of Virology
Epstein-Barr virus (EBV) infection of primary B cells causes B-cell activation and proliferation. Activation of B cells requires binding of antigen to the B-cell receptor and a survival signal from ligand-bound CD40, signals that are provided by the EBV LMP1 and LMP2A latency proteins. Recently, Toll-like receptor (TLR) signaling has been reported to provide a third B-cell activation stimulus. The interaction between the EBV and TLR pathways was therefore investigated. Both UV-inactivated and untreated EBV upregulated the expression of TLR7 and downregulated the expression of TLR9 in naive B cells. UV-inactivated virus transiently stimulated naive B-cell proliferation in the presence of the TLR7 ligand R837, while addition of the TLR7 antagonist IRS 661 impaired cell growth induced by untreated EBV. Interferon regulatory factor 5 (IRF-5) is a downstream mediator of TLR7 signaling. IRF-5 was induced following EBV infection, and IRF-5 was expressed in B-cell lines with type III latency. Expression of IRF-5 in this setting is surprising since IRF-5 has tumor suppressor and antiviral properties. B-cell proliferation assays provided evidence that EBV modulates TLR7 signaling responses. Examination of IRF-5 transcripts identified a novel splice variant, V12, that was induced by EBV infection, was constitutively nuclear, and acted as a dominant negative form in IRF-5 reporter assays. IRF-4 negatively regulates IRF-5 activation, and IRF-4 was also present in type III latently infected cells. EBV therefore initially uses TLR7 signaling to enhance B-cell proliferation and subsequently modifies the pathway to regulate IRF-5 activity.

 

Tagging recombinant proteins to enhance solubility and aid purification
  Dermot Walls, Sinéad T Loughran      2011      Protein Chromatography
Protein fusion technology has enormously facilitated the efficient production and purification of individual recombinant proteins. The use of genetically engineered affinity and solubility-enhancing polypeptide “tags” has increased greatly in recent years and there now exists a considerable repertoire of these that can be used to solve issues related to the expression, stability, solubility, folding, and purification of their fusion partner. In the case of large-scale proteomic studies, the development of purification procedures tailored to individual proteins is not practicable, and affinity tags have therefore become indispensable tools for structural and functional proteomic initiatives that involve the expression of many proteins in parallel. Here, the rationale and applications of a range of established and more recently developed solubility-enhancing and affinity tags are outlined.

 

The bfl-1 gene is transcriptionally upregulated by the Epstein-Barr virus LMP1, and its expression promotes the survival of a Burkitt's lymphoma cell line
  Triona M. O'Connell, Damien King, Chandra K Dixit, Brendan O'Connor, Dermot Walls, Jens DucréeBrendan D'Souza, Martin Rowe, Dermot Walls      2000      Journal of Virology

The recently identified bfl-1 gene (also known asA1 or GRS), a homologue of bcl-2, encodes an antiapoptotic protein that suppresses apoptosis induced by the p53 tumor suppressor protein and exhibits proliferative and potent cooperative transforming activities. We show that elevated levels of bfl-1 mRNA are a feature of Epstein-Barr virus (EBV)-immortalized B-cell lines and Burkitt’s lymphoma cell lines expressing the full spectrum of EBV latent proteins. Using an EBV-negative Burkitt’s lymphoma cell line in which the expression of EBV latent membrane protein 1 (LMP1) is inducibly regulated by tetracycline, we demonstrate that LMP1 expression coincides with a dramatic increase in the level ofbfl-1 mRNA. Also in this system, an increase in the level of Bcl-2 protein was seen to occur earlier than that ofbcl-2 mRNA, suggesting that both transcriptional and translational mechanisms are involved in the control of Bcl-2 expression by LMP-1. We show that elevated bfl-1mRNA stability can contribute to this effect of LMP-1, thus providing evidence of a novel mechanism of gene regulation by this EBV protein. Upregulation ofbfl-1 by LMP1 was not observed in the T-cell line Jurkat or the epithelial cell line C33A. Ectopic expression of Bfl-1 in an EBV-positive cell line exhibiting a latency type I infection protects against apoptosis induced by growth factor deprivation, thereby providing a functional role for Bfl-1 in this cellular context and adding Bfl-1 to the list of antiapoptotic proteins whose expression is modulated by EBV. This is the first report of the regulation of bfl-1expression by a viral protein, and this novel finding may thus represent an important link between the EBV oncoprotein LMP1 and its cellular growth-transforming properties.

 

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