Molecular biology of RNA picornaviruses; protein translation,
proteolytic processing; RNA synthesis; viral pathogenesis; viral
vaccines, vaccine vectors; computer-based sequence analysis
We
are interested in all aspects of picornavirology. Among our major goals
are to explore and define the relationship of the cardiovirus genus to
other members of the picornavirus family and to exploit the unique
features of the cardioviruses to examine molecular questions about
picornavirus translation, proteolytic processing, morphogenesis and
pathogenicity. In contrast to many other viral genomes, cardioviral RNA
is translated with unusually high efficiency in cell-free extracts.
This provides a unique experimental system for examining viral protein
expression and virion assembly. Everything we have learned about the
molecular biology of these viruses provides an experimental foundation
for study of the more virulent isolates such as foot-and-mouth disease
virus, polio, coxsackie, hepatitis A, rhinovirus, etc. Isolates of
Theiler's virus (murine encephalomyelitis), for example, and variants
of EMC (encephalomyocarditis) are being studied as models in human
diseases like multiple sclerosis and forms of insulin-dependent
diabetes.
Our laboratory has developed an extensive
panel of infectious cardiovirus cDNAs (EMC and Mengo), and we use
high-tech recombinant engineering, reverse genetics and cell-free
protein synthesis techniques to unravel the virus life cycle, step by
step. Current projects include: 1) characterization of proteolytic
agents involved in the viral protein cleavage cascade; 2) design and
testing of anti-protease, anti-viral agents; 3) investigating the role
of long 5' non-coding sequences (and polyC tracts) in viral translation
and ribosome interactions; 4) engineered expression and isolation of
non-structural proteins for enzymology and crystallography; 5) the
mechanism of viral RNA replication.
Additionally, some
of our genetically engineered viruses have proven to be superb live
attenuated vaccines, capable of providing effective, long-lived
anti-picornavirus immunity in virtually all species of mammals,
including primates. We are exploiting these constructions for the
prevention of picornavirus disease, but have also harnessed these
agents into novel, recombinant vaccine vectors, that can deliver
efficacious protection against HIV, SIV, rabies, murine malaria, and a
variety of other infectious diseases. Therefore, another major research
direction is the characterization of the molecular basis for viral
attenuation in these cardioviruses with the objective of exploiting
this phenomena and the principles to be learned from it, for the
development of new and effective vaccine treatments.
We
are also experimentally active in the development of computer methods
for analyzing viral sequences, the prediction of the topological
folding of large viral RNA genomes, computer-based visualization of
virus surfaces and genomic-based virus taxonomy. We maintain widely
used databases of viral protein and RNA sequences and are investigating
new methods for genomic-based virus identification and taxonomy.