| Summary: | 碩士 === 國立臺灣大學 === 漁業科學研究所 === 89 === Abstract
Infectious Pancreatic Necrosis Virus (IPNV) belonging to the Birnaviridae with bisegmented double-strand RNA genomes is one of the widespread fish pathogen and could infect many economically important finfish and shellfish. According to previous study in our laboratory, IPNV infection could induce apoptosis in chinook salmon embryo cell line CHSE-214. To clarify the regulation mechanism in IPNV-induced apoptosis, this thesis is attempted to identify host cell transcription factors involved in this apoptosis response, especially nuclear factor-kappa B (NF-kB) and cyclic-AMP-response-element-binding protein (CREB) that are well known to play important roles in the regulation of apoptosis in other systems.
As determined in electrophoretic mobility shift assays, IPNV infection in CHSE-214 cells leads to activation of NF-kB and CREB at 8 hours post infection. Treatment of IPNV-infected CHSE cells with a tyrosine kinase inhibitor (Genistein) prevents NF-kB and CREB activation and suggests tyrosine kinases are key regulators in signaling pathway of IPNV-induced apoptosis. IPNV-induced activation of NF-kB DNA-binding activity correlated with the onset of NF-kB-directed expression of reporter gene in trans-activation assay. Treatments of IPNV-infected CHSE cells with proteasome inhibitor I and II inhibit NF-kB activation and substantially diminish IPNV-induced apoptosis from 43.1 % to 12.5 % and 14.7 % which were quantitated by Hoechst 33258 and Acridine Orange staining. Finally, these two inhibitors have no influence on viral protein expression of IPNV by Western Blotting.
These findings indicate that the signaling of IPNV-induced apoptosis in CHSE-214 cells is transmitted by tyrosine kinases and via the activation of transcription factor NF-kB.
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