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Janet Hearing

Publications

 

 

 
Janet Hearing

Associate Professor

Ph.D., Stony Brook University, 1984
270 Life Sciences Building

E-mail:
Office:
Fax:


(631) 632-8778
(631) 632-9162

   
Research

Development of Antiviral Drugs to Combat Influenza

Immunization is the front-line defense against influenza but, as illustrated by the response to the 2009 H1N1 pandemic, this defense is not without significant problems. It takes months to develop a specific vaccine, initial demand for the vaccine can exceed supplies, and skepticism from the public can contribute to low coverage. Non-pharmaceutical interventions, together with the neuraminidase inhibitor oseltamivir, are used to prevent and treat infections at the inception of a pandemic but the use of oseltamivir is often compromised by the rapid emergence of drug-resistant strains. A major focus of the laboratory is to identify novel inhibitors of the influenza virus neuraminidase, a validated drug target. We are screening compounds identified in a virtual high throughput screen for neuraminidase inhibitory activity and characterizing the mode of inhibition for hits. In a separate project, we are developing a high throughput screen for the identification of inhibitors of the influenza virus polymerase.

 

Replication and maintenance of the Epstein-Barr virus genome in latently infected cells

 
  Atomic Force Microscopic Image of EBNA-1 Bound Site-Specifically to DNA

Epstein-Barr virus (EBV), a member of the herpesvirus family, causes lifelong infections in humans. Approximately 90% of the world's adult population is infected with EBV and although most of these infections are benign, EBV is causally associated with certain human cancers of B-lymphocytes and epithelial cells. The EBV genome, a double-stranded DNA molecule of ~170 kbp, is present within EBV-positive tumor cells as a multicopy plasmid. EBV plasmids are each replicated once per cell cycle during S phase and are efficiently partitioned between daughter cells during mitosis. The best characterized EBV replication origin utilized in latently-infected cells is located adjacent to a sequence element required for plasmid maintenance and, together, these two elements are referred to as oriP. Small recombinant plasmids bearing oriP are also replicated in a cell cycle-regulated manner and the replication and the long-tem maintenance of these oriP-plasmids requires only a single viral protein, the EBV nuclear antigen-1 (EBNA-1). Due to the availability of quantitative short-term replication assays for oriP-plasmids and the almost comlete dependence of oriP-plasmid replication upon cellular proteins, oriP provides an extremely attractive system with which to investigate the regulated initiation of DNA replication from human chromosomal replication origins.

A long-term goal of this laboratory is to obtain a detailed molecular description of the mechanisms by which replication initiates within oriP. EBNA-1 binds site-specifically to four sites within the oriP replicator and bends the DNA but is unable to unwind the duplex in preparation for daughter strand synthesis. Therefore, it is likely that cellular replication proteins carry out this early step in oriP-plasmid DNA replication. We have determined that the oriP replicator contains a core element, consisting of two EBNA-1 binding sites flanked by inverted copies of a 14-bp repeat, that is essential for activity and multiple ancillary elements that are required for full activity. The results of our genetic analysis of the oriP replicator suggest that a host cell protein binds to nucleotides within the 14-bp repeats and interacts with EBNA-1 to promote the initiation of DNA replication. It was recently shown that the human origin recognition complex (ORC), minichromosome maintenance protein complex (MCM), and geminin participate in the regulated replication of plasmids bearing oriP. Our current efforts are directed at identifying the protein and sequence requirements for the physical and functional association of human replication proteins with the replicator of oriP and determining the contribution of ancillary elements to replicator function.

Department of Molecular Genetics and Microbiology
Stony Brook University
Stony Brook, New York 11794-5222
Phone: 631-632-8800
Fax: 631-632-9797

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