The role of viral proteins in the pathogenesis of infectious hematopoietic necrosis
virus (IHNV) was studied at the molecular level. The expression of the viral genes at the
protein and RNA level, and their cellular localization, were characterized to further our
understanding of viral pathogenesis. The pathogenic effect of individual viral proteins was
also investigated and a method for detecting viral RNA in infected fish tissues was
developed.
The polarity of transcription was confirmed in terms of the relative amounts of each
viral protein. Also, cells treated with glycosylation inhibitors did not exhibit cytopathic
effect, demonstrating that a functioning host glycosylation system is necessary for viral
replication. These studies also revealed a previously undescribed non-glycosylated protein,
S, which appeared to be virus-encoded. The expression of the nonvirion protein (NV), was
also detected in infected kidney tissues. The location of M2 and NV in the cell was found to
be the nucleus and cytoplasm.
The expression of the NV gene was further analyzed at the level of transcription and
the regulation signals for IHNV transcription were investigated. Unique transcriptional
initiation and terminational signals for the fish lyssa-like rhabdoviruses were identified. The
transcriptional initiation signal, 3'-CGUG-5', was distinctly different from that of the other
rhabdoviruses, 3'-UUGU-5'.
The role of the M2 and NV proteins in viral pathogenesis was investigated by
transient expression of these proteins individually in cultured fish cells. The M2 protein
alone resulted in inhibition of host-directed gene expression at the level of transcription and
induction of nuclear fragmentation. The NV protein was not involved in the regulation of
the host gene expression, but was involved in another type of cytopathic effect characterized
as cell rounding. This is the first biological function attributed to the NV protein.
A PCR method was developed for detecting IHNV N-specific RNA in formalin-fixed,
paraffin-embedded fish tissues. The method is sensitive and specific. The technique
is capable of detecting viral RNA in samples that have been remained at room temperature in
10% buffered formalin for over 2 years. / Graduation date: 1997
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/34192 |
| Date | 11 December 1996 |
| Creators | Chiou, Pinwen Peter |
| Contributors | Leong, Jo-Ann C. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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