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Three functionally diverged major structural proteins of white spot syndrome virus evolved by gene duplication
Mariëlle C W van Hulten1, Rob W Goldbach1, Just M Vlak1
1Laboratory of Virology, Wageningen University, Binnenhaven 11, 6709 PD Wageningen, The Netherlands1.
Abstract:
White spot syndrome virus (WSSV) is an invertebrate virus causing considerable mortality in penaeid shrimp. The oval-to-bacilliform shaped virions, isolated from infected Penaeus monodon, contain four major proteins: VP28, VP26, VP24 and VP19 (28, 26, 24 and 19 kDa, respectively). VP26 and VP24 are associated with the nucleocapsid and the remaining two with the envelope. Forty-one N-terminal amino acids of VP24 were determined biochemically allowing the identification of its gene (vp24) in the WSSV genome. Computer-assisted analysis revealed a striking similarity between WSSV VP24, VP26 and VP28 at the amino acid and nucleotide sequence level. This strongly suggests that these structural protein genes may have evolved by gene duplication and subsequently diverged into proteins with different functions in the WSSV virion, i.e. envelope and nucleocapsid. None of these three structural WSSV proteins showed homology to proteins of other viruses including baculoviruses, underscoring the distinct taxonomic position of WSSV among invertebrate viruses.
Insights
White spot syndrome virus (WSSV) causes shrimp mortality. Its major structural proteins VP24, VP26, and VP28 likely evolved from gene duplication, showing distinct viral evolution.
Area of Science:
- Virology
- Molecular Biology
- Aquaculture
Background:
- White spot syndrome virus (WSSV) is a significant pathogen in penaeid shrimp aquaculture.
- WSSV infection leads to high mortality rates in farmed shrimp populations.
- Understanding WSSV structural proteins is crucial for disease management.
Purpose of the Study:
- To biochemically characterize WSSV structural proteins.
- To identify the gene encoding the WSSV VP24 protein.
- To investigate the evolutionary relationship between WSSV structural proteins.
Main Methods:
- Biochemical determination of N-terminal amino acids of VP24.
- Identification of the vp24 gene within the WSSV genome.
- Computer-assisted sequence analysis of WSSV structural proteins.
Main Results:
- The WSSV virion contains four major proteins: VP28, VP26, VP24, and VP19.
- VP26 and VP24 are nucleocapsid-associated; VP28 and VP19 are envelope-associated.
- Sequence analysis revealed significant similarity between VP24, VP26, and VP28, suggesting a common evolutionary origin via gene duplication.
- No homology was found with proteins from other viruses, including baculoviruses.
Conclusions:
- The structural proteins VP24, VP26, and VP28 of WSSV likely evolved through gene duplication and subsequent divergence.
- These findings highlight the unique evolutionary path of WSSV among invertebrate viruses.
- The distinct nature of WSSV proteins supports its unique taxonomic classification.