Prof David Rowlands
Dave Rowlands is Professor of Molecular Virology in the Institute of Molecular and Cellular Biology in the Faculty of Biological Sciences, University of Leeds. He obtained his B.Sc. in Zoology from Kings College, London in 1961 and his Ph.D. in Biochemistry from the University of Southampton in 1967. He then worked at the Agricultural Research Council (now BBSRC) Animal Virus Research Institute, Pirbright, before joining Wellcome Biotech in 1983. He left Wellcome to join the University of Leeds in 1996.
Research Areas: Structure and Replication Strategies of RNA Viruses
Research interests: David Rowlands has a long standing interest in molecular aspects of the structure and replication strategies of RNA viruses, having worked for many years on foot and mouth disease virus. During that time the organisation of the virus genome was elucidated and the crystal structure of the virion was solved. At Wellcome he became interested in the human hepatitis viruses and worked with hepatitis A, B and C viruses. These studies became focussed on hepatitis C virus as a target for the development of anti-viral therapeutic drugs. At Leeds he, together with Drs Mark Harris and Dick Killington and in close collaboration with Dr Jo Jaeger, has established a laboratory centred principally on hepatitis C virus but which is expanding to include hepatitis B virus, human rhinovirus and others.
Hepatitis C virus:
Hepatitis C virus (HCV) was only identified in 1989 by the application of sophisticated molecular cloning strategies. It is virtually impossible to culture in vitro and the chimpanzee is the only non-human animal known to be susceptible to infection by the virus. The large majority of patients who are infected with the virus become chronic carriers for the rest of their lives and it is estimated that there are approximately 170 millions carriers world-wide. Acute infections are usually mild or asymptomatic and the development of serious liver disease usually occurs long after the initial infection. Most infected individuals never develop clinically serious disease and the factors which determine the pathological consequences of persistent infection are not understood. There is no vaccine, or prospect of a vaccine, and current therapies are only effective in the minority of cases. HCV is now the single most important association factor for disease requiring liver transplant surgery in the USA and UK.
HCV is a positive strand RNA virus in the Flavivirus family and we are investigating many aspects of its structure and replication, including interactions between virus and host cell components. Of necessity, most of these studies involve the expression of viral proteins using recombinant techniques since there is no laboratory virus infection system. However, it has been reported recently that artificially constructed molecules, in which the structural protein coding region of the virus is replaced by a selectable marker gene, will replicate in cells and we are applying this technology in our work.
5? UTR- HCV, in common with some other RNA viruses, initiates protein synthesis by a process that is distinct from the CAP dependent mechanism typical for most eukaryotic mRNAs. A complex and highly conserved structure known as the internal ribosome entry site (IRES) lies within the 5? untranslated region of the viral RNA and acts as a scaffold upon which ribosomes assemble directly without the requirement for the CAP binding machinery. Although the secondary structure of the IRES is reasonably well established there is little information on the tertiary structure. In collaboration with Dr Jo Jaeger, Dr Andreas Holzenburg (University of Texas) and Prof Alastair Smith (Physics) we are using X ray crystallography, electron microscopy and atomic force microscopy in an attempt to learn more about the structure of the IRES and its interaction with cellular factors.
Structural proteins ? HCV encodes a nucleocapsid protein (core) and two envelope proteins. A bewildering array of cell protein interactions with these viral components has been described, especially with the core protein, but there is little information on the mechanism of virus particle assembly. There are also conflicting reports on the cell receptors utilised by the virus. We are using mammalian cell expression systems in attempts to generate HCV particles incorporating the genome of a second virus in order to address some of these problems.
P7 ? This is a small protein located on the viral genome at the boundary between the structural protein and non-structural protein coding regions. It is highly conserved but its function is unknown. Recent studies with bovine viral diarrhoea virus have shown that the equivalent protein in that virus is not required for genome replication but is essential for the production of infectious virus particles. We, in collaboration with other colleagues in the Astbury Centre and the School of Physics (D.Evans), are about to embark on a physico-chemical study of the properties of this protein in an attempt to elucidate its function.
Polymerase ? In collaboration with Dr Jo Jaeger we have expressed and purified a highly active RNA dependant RNA polymerase from the virus and the crystal structure has been solved to a resolution of 2.3 Å. Biochemical properties of the enzyme are being studied by a variety of methods, including a novel assay developed by a post doctoral fellow, Dr Henric Ekstrand, which is the platform technology for start up company (RepliZyme). The structural information is being used to guide rational mutagenesis experiments coupled with biochemical studies to understand better the functioning of the enzyme. However, the polymerase enzyme is only one component of the full replication machinery of the virus and we are studying its interaction with other viral and cellular factors to form the replication complex. We are embarking on parallel studies of the replication machinery of Picornaviruses.
Replication ? It is important to compare the biological properties of virus proteins when studied in isolation from other viral components with their properties when expressed in the natural context of the full viral genome. This is inherently difficult with HCV because of the lack of a laboratory virus infection system. We are addressing these issues by the development of replicons; which are viral genome deletion mutants capable of independent replication and incorporating a selectable genetic marker.
Rhinoviruses belong to the Picornavirus family and are responsible for the majority of human colds. They are also a major factor in the exacerbation of asthma ? a problem of increasing importance. We are studying the replication of human rhinoviruses in murine epithelial cells with the ultimate goal of developing a mouse model for the exacerbation of asthma, as seen in humans. We are also studying the interaction of rhinoviruses with a naturally occurring mutant of the virus receptor molecule, ICAM 1, which is found at a high frequency in African populations.
Hepatitis B virus:
The nucleocapsid, or core, protein of hepatitis B virus assembles into virus like particles when expressed by recombinant techniques. Modified core protein carrying inserted foreign sequence retains the self-assembly property and is being investigated as the basis for the development of novel vaccines. We are also interested in the envelope glycoproteins of the virus and are involved in a collaborative project with researchers in London and Oxford to determine the structure of the surface antigen particle. This constitutes the current hepatitis B virus vaccine and is the first recombinant vaccine.
Research funding: BBSRC, MRC, Wellcome Trust & European Union.
Institute of Molecular and Cellular Biology
Garstang South Building
University of Leeds
Phone: 0113 343 5641
Fax: 0113 343 5638
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