The Betanodaviruses caused nerve necrosis in several fishes. There are two RNAs in the Betanodaviruses. RNA1 encodes RNA dependent RNA polymerase and RNA2 encodes capsid protein. I analyzed the RNA2 sequences of the viruses isolated from two species of grouper, Epinephelus malabaricus (MGNNV) and E. lanceolatus (DGNNV). The similarity of two grouper viruses (GNNV) was 99%. Their similarities to DlEV and SJNNV were 87.8% and 78.6%, respectively. The capsid protein was successful expressed and assembled to virus-like particles.
Deleting N- and C-termini revealed different impacts on VLP formation. Deletion of 35 or 52 residues at the N-terminus completely ruined the VLP assembly, presumably due to removal of positively charged residues for binding RNAs. When deletions were restricted to 4, 16, or 25 N-terminal residues, the assembly of VLPs remained. The ability of VLP formation diminished when 4 to 11 C-terminal residues were deleted. The termini that can be deleted without seriously destructing the VLPs are 25 and 3 residues at N- and C-termini, respectively.
Expression the ORF of RNA2 in E. coli formed virus-like particles, indistinguishable from native virus particles in appearance, whereas a mutant of Asp-75 expressed no VLPs. The emergence of a trimer band in mutant D75N as wild type suggested that the Asp-75 mutation could halt the packaging process in the trimer stage, not proceeding to assemble intact VLPs. The D54N mutant remained the ability of VLP formation but lost packaging high molecular weight of RNAs. Another Asp mutant at C-terminus, D335A, lost the ability of VLP assembly. The D335 may play an important role on the instability of VLP structure.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0115103-192739 |
| Date | 15 January 2003 |
| Creators | Lu, Ming-Wei |
| Contributors | Chan-Shing Lin, Chi-Hsin Hsu, Chung-Lung Cho, Yi-Ren Hong, H. L. Wang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0115103-192739 |
| Rights | campus_withheld, Copyright information available at source archive |
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