Transcriptional analysis of the white spot syndrome virus major virion protein genes.
TL;DR: Transcription of the major WSSV structural virion protein genes was studied to search for common promoter motifs for coordinate expression and revealed a consensus late transcription initiation motif for only two of the five major virionprotein genes.
Abstract: White spot syndrome virus (WSSV) is a member of a new virus family (Nimaviridae) infecting crustaceans. The regulation of transcription of WSSV genes is largely unknown. Transcription of the major WSSV structural virion protein genes, vp28, vp26, vp24, vp19 and vp15, was studied to search for common promoter motifs for coordinate expression. The temporal expression of these genes and both 5' and 3' ends of the mRNA were determined, using infected crayfish gill tissue as a RNA source. RT-PCR showed that all five genes are expressed late in infection compared to the early ribonucleotide reductase large subunit gene. 5' RACE studies revealed a consensus late transcription initiation motif for only two of the five major virion protein genes. This motif was only found in one other upstream region of the putative translational start site of a gene with unknown function (ORF 158). No other conserved sequence motifs could be detected in the sequences surrounding the transcriptional start sites of the five major virion protein genes. All 5' ends were located about 25 nt downstream of an A/T rich sequence, including the consensus TATA-box sequence for vp15. The absence of a consensus motif is distinct from gene regulation of other large dsDNA viruses and suggests a unique regulation of WSSV transcription, in line with its unique taxonomic position.
Citations
More filters
TL;DR: Contrary to current assumptions that invertebrates do not have a true adaptive immune system, a specific immune response and protection can be induced in P. monodon, and these experiments open up new ways to benefit the WSSV-hampered shrimp farming industry.
Abstract: White spot syndrome virus (WSSV) occurs worldwide and causes high mortality and considerable economic damage to the shrimp farming industry. No adequate treatments against this virus are available. It is generally accepted that invertebrates such as shrimp do not have an adaptive immune response system such as that present in vertebrates. As it has been demonstrated that shrimp surviving a WSSV infection have higher survival rates upon subsequent rechallenge, we investigated the potential of oral vaccination of shrimp with subunit vaccines consisting of WSSV virion envelope proteins. Penaeus monodon shrimp were fed food pellets coated with inactivated bacteria overexpressing two WSSV envelope proteins, VP19 and VP28. Vaccination with VP28 showed a significant lower cumulative mortality compared to vaccination with bacteria expressing the empty vectors after challenge via immersion (relative survival, 61%), while vaccination with VP19 provided no protection. To determine the onset and duration of protection, challenges were subsequently performed 3, 7, and 21 days after vaccination. A significantly higher survival was observed both 3 and 7 days postvaccination (relative survival, 64% and 77%, respectively), but the protection was reduced 21 days after the vaccination (relative survival, 29%). This suggests that contrary to current assumptions that invertebrates do not have a true adaptive immune system, a specific immune response and protection can be induced in P. monodon. These experiments open up new ways to benefit the WSSV-hampered shrimp farming industry.
343 citations
TL;DR: This review provides a state-of-the-art overview of the white spot syndrome virus, and emphasizes the current progress and future direction for the development of WSSV control strategies.
Abstract: Viruses are ubiquitous and extremely abundant in the marine environment. One of such marine viruses, the white spot syndrome virus (WSSV), has emerged globally as one of the most prevalent, widespread and lethal for shrimp populations. However, at present there is no treatment available to interfere with the unrestrained occurrence and spread of the disease. The recent progress in molecular biology techniques has made it possible to obtain information on the factors, mechanisms and strategies used by this virus to infect and replicate in susceptible host cells. Yet, further research is still required to fully understand the basic nature of WSSV, its exact life cycle and mode of infection. This information will expand our knowledge and may contribute to developing effective prophylactic or therapeutic measures. This review provides a state-of-the-art overview of the topic, and emphasizes the current progress and future direction for the development of WSSV control strategies.
281 citations
TL;DR: White spot syndrome virus (WSSV) virions were purified from the hemolymph of experimentally infected crayfish Procambarus clarkii, and their proteins were separated by 8 to 18% gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to give a protein profile.
Abstract: White spot syndrome virus (WSSV) virions were purified from the hemolymph of experimentally infected crayfish Procambarus clarkii, and their proteins were separated by 8 to 18% gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to give a protein profile. The visible bands were then excised from the gel, and following trypsin digestion of the reduced and alkylated WSSV proteins in the bands, the peptide sequence of each fragment was determined by liquid chromatography-nano-electrospray ionization tandem mass spectrometry (LC-nanoESI-MS/MS) using a quadrupole/time-of-flight mass spectrometer. Comparison of the resulting peptide sequence data against the nonredundant database at the National Center for Biotechnology Information identified 33 WSSV structural genes, 20 of which are reported here for the first time. Since there were six other known WSSV structural proteins that could not be identified from the SDS-PAGE bands, there must therefore be a total of at least 39 (33 + 6) WSSV structural protein genes. Only 61.5% of the WSSV structural genes have a polyadenylation signal, and preliminary analysis by 3' rapid amplification of cDNA ends suggested that some structural protein genes produced mRNA without a poly(A) tail. Microarray analysis showed that gene expression started at 2, 6, 8, 12, 18, 24, and 36 hpi for 7, 1, 4, 12, 9, 5, and 1 of the genes, respectively. Based on similarities in their time course expression patterns, a clustering algorithm was used to group the WSSV structural genes into four clusters. Genes that putatively had common or similar roles in the viral infection cycle tended to appear in the same cluster.
241 citations
Cites background from "Transcriptional analysis of the whi..."
...monodon (vp28, vp26, vp24, vp19, and vp15) are in agreement with the 3 ends of these genes as determined from RNA isolated from WSSV-infected crayfish (Orconectes limosus) (28)....
[...]
TL;DR: Large dsRNA molecules as well as siRNAs induce a sequence-independent anti-viral immunity when injected in shrimp, indicating an alternative and more specific approach to counteract WSSV infections in shrimp by the exploitation of RNA interference.
147 citations
TL;DR: Results clearly showed that rALFPm3 was able to reduce WSSV propagation and prolong the survival of shrimps.
Abstract: The anti-lipopolysaccharide factor (ALF) from the black tiger shrimp, Penaeus monodon, has been shown previously to exhibit a broad spectrum of activity against various strains of bacteria and fungi. Herein, the recombinant ALFPm3 (rALFPm3) protein was examined for its role in the defence against white spot syndrome virus (WSSV) infection in haematopoietic (Hpt) cell cultures of the freshwater crayfish, Pacifastacus leniusculus, as well as in live P. monodon shrimps. Incubation of Hpt cell cultures with a mixture of WSSV and rALFPm3 resulted in a dose-dependent decrease in VP28 gene expression levels, compared with those incubated with WSSV alone, with an rALFPm3 IC50 value lower than 2.5 microM. However, pre-treatment of Hpt cells with 5 microM rALFPm3 showed no induced protection against subsequent WSSV infection, whereas the synthetic crayfish ALF peptide could protect cells at a higher concentration (10 microM). The in vivo role of ALFPm3 was examined by injection of P. monodon with WSSV pre-treated with rALFPm3 protein. The results clearly showed that rALFPm3 was able to reduce WSSV propagation and prolong the survival of shrimps.
101 citations
Cites background from "Transcriptional analysis of the whi..."
...The gene encoding the viral envelope protein, VP28, is one of the late genes and is expressed after replication of the viral genome (Marks et al., 2003, 2005)....
[...]
References
More filters
TL;DR: The small (40S) subunit of eukaryotic ribosomes is believed to bind initially at the capped 5'-end of messenger RNA and then migrate, stopping at the first AUG codon in a favorable context for initiating translation.
Abstract: The small (40S) subunit of eukaryotic ribosomes is believed to bind initially at the capped 5'-end of messenger RNA and then migrate, stopping at the first AUG codon in a favorable context for initiating translation. The first-AUG rule is not absolute, but there are rules for breaking the rule. Some anomalous observations that seemed to contradict the scanning mechanism now appear to be artifacts. A few genuine anomalies remain unexplained.
3,389 citations
"Transcriptional analysis of the whi..." refers methods in this paper
...The nucleotides surrounding the methionine start codons of the five major structural protein genes are consistent with the Kozak rule for efficient eukaryotic translation initiation (Kozak, 1989)....
[...]
01 Jan 1997
2,567 citations
"Transcriptional analysis of the whi..." refers methods in this paper
...Sequence data were analysed using the software package DNASTAR 4.2 and the data were edited in GeneDoc, version 2.6.000 (Nicholas et al., 1997)....
[...]
TL;DR: Three effects of deletion mutations on polyadenylation of late SV40 mRNAs are observed, including a 16 bp deletion that includes the AAUAAA sequence that prevents poly(A) addition.
640 citations
"Transcriptional analysis of the whi..." refers background in this paper
...All identified WSSV polyadenylation sites are within the range of regular polyadenylation in eukaryotic mRNAs, which is typically located 15 to 25 nt downstream of the sequence AAUAAA (Fitzgerald & Shenk, 1981)....
[...]
TL;DR: The collective information on WSSV and the phylogenetic analysis on the viral DNA polymerase suggest that W SSV differs profoundly from all presently known viruses and that it is a representative of a new virus family.
582 citations
TL;DR: The first complete genome sequence of a marine invertebrate virus, White spot bacilliform virus is reported, indicating that WSBV differs from all known viruses, although a few genes display a weak homology to herpesvirus genes.
Abstract: We report the first complete genome sequence of a marine invertebrate virus. White spot bacilliform virus (WSBV; or white spot syndrome virus) is a major shrimp pathogen with a high mortality rate and a wide host range. Its double-stranded circular DNA genome of 305,107 bp contains 181 open reading frames (ORFs). Nine homologous regions containing 47 repeated minifragments that include direct repeats, atypical inverted repeat sequences, and imperfect palindromes were identified. This is the largest animal virus that has been completely sequenced. Although WSBV is morphologically similar to insect baculovirus, the two viruses are not detectably related at the amino acid level. Rather, some WSBV genes are more homologous to eukaryotic genes than viral genes. In fact, sequence analysis indicates that WSBV differs from all known viruses, although a few genes display a weak homology to herpesvirus genes. Most of the ORFs encode proteins that bear no homology to any known proteins, either suggesting that WSBV represents a novel class of viruses or perhaps implying a significant evolutionary distance between marine and terrestrial viruses. The most unique feature of WSBV is the presence of an intact collagen gene, a gene encoding an extracellular matrix protein of animal cells that has never been found in any viruses. Determination of the genome of WSBV will facilitate a better understanding of the molecular mechanism underlying the pathogenesis of the WSBV virus and will also provide useful information concerning the evolution and divergence of marine and terrestrial animal viruses at the molecular level.
542 citations
"Transcriptional analysis of the whi..." refers background in this paper
...Splicing events can be excluded for these mRNAs, as has been demonstrated by the cloning and sequencing of cDNAs (Yang et al., 2001) and the expression of the VPs in insect cells (van Hulten et al....
[...]
...Its dsDNA genome of around 300 kb (van Hulten et al., 2001a; Yang et al., 2001; AF440570) is among the largest viral genomes, but little is known about gene regulation of this virus....
[...]
...Sequencing of three different WSSV isolates revealed that the dsDNA genome is about 300 kb in size (vanHulten et al., 2001a; Yang et al., 2001; GenBank acc. no....
[...]
...Splicing events can be excluded for these mRNAs, as has been demonstrated by the cloning and sequencing of cDNAs (Yang et al., 2001) and the expression of the VPs in insect cells (van Hulten et al., 2002)....
[...]