Taxonomic distribution of proteins containing SVWC domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing SVWC domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Identification and functional characterization of Dicer2 and five single VWCdomain proteins of Litopenaeus vannamei.

Chen YH, Jia XT, Zhao L, Li CZ, Zhang S, Chen YG, Weng SP, He JG
Dev Comp Immunol. 2011; 35: 661-71

Dicer (Dcr) is the key protein of the RNA interference (RNAi) pathway. Toinvestigate the role of the RNAi pathway in shrimp anti-viral immunity,Litopenaeus vannamei Dcr2 (designated as LvDcr2) was identified andcharacterized. The full-length cDNA of LvDcr2 was 5513bp long, with an openreading frame encoding a putative protein of 1502 amino acids. In addition, five proteins homologous to the single von Willebrand factor type C (VWC) domainprotein (SVC) were also identified in L. vannamei and named LvSVC1-5. TheseLvSVCs were between 102 and 190 amino acids in length and all contained a motifsimilar to Drosophila melanogaster SVC proteins (DmSVCs). Byco-immunoprecipitation assays and pull-down assays, we demonstrated that LvDcr2, L. vannamei Argonaute 2 (LvAgo2), and L. vannamei transactivating responseRNA-binding protein isoform 1 (LvTRBP1) interacted with each other. A luciferase reporter assay indicated that the promoters of LvSVC1, LvSVC4, LvSVC5, and DmSVC Vago (DmVago) were activated by LvDcr2 as well as by Drosophila Dcr2 (DmDcr2).Real-time RT-PCR showed that LvDcr2 and LvSVCs were up-regulated in immuneresponses against Poly(C-G) or WSSV challenge. These results suggested thatLvDcr2 formed complexes with LvAgo2 and LvTRBP1 to act as the cores of shrimpsmall interfering RNA (siRNA)-induced silencing complex (siRISC)/siRISC-loadingcomplex (siRLC), role in shrimp siRNA pathway. Furthermore, these results alsosuggested that LvDcr2 may engage in non-specific activation of anti-viralimmunity.

A further insight into the sialome of the tropical bont tick, Amblyommavariegatum.

Ribeiro JM, Anderson JM, Manoukis NC, Meng Z, Francischetti IM
BMC Genomics. 2011; 12: 136-136

BACKGROUND: Ticks--vectors of medical and veterinary importance--are themselvesalso significant pests. Tick salivary proteins are the result of adaptation toblood feeding and contain inhibitors of blood clotting, platelet aggregation, andangiogenesis, as well as vasodilators and immunomodulators. A previous analysisof the sialotranscriptome (from the Greek sialo, saliva) of Amblyomma variegatum is revisited in light of recent advances in tick sialomes and provides a databaseto perform a proteomic study. RESULTS: The clusterized data set has been expertlycurated in light of recent reviews on tick salivary proteins, identifying manynew families of tick-exclusive proteins. A proteome study using salivary glandhomogenates identified 19 putative secreted proteins within a total of 211matches. CONCLUSIONS: The annotated sialome of A. variegatum allows itscomparison to other tick sialomes, helping to consolidate an emerging pattern in the salivary composition of metastriate ticks; novel protein families were alsoidentified. Because most of these proteins have no known function, the task offunctional analysis of these proteins and the discovery of novelpharmacologically active compounds becomes possible.

Mass spectrometry analysis, amino acid sequence and biological activity of venom components from the Brazilian scorpion Opisthacanthus cayaporum.

Schwartz EF, Camargos TS, Zamudio FZ, Silva LP, Bloch C Jr, Caixeta F, Schwartz CA, Possani LD
Toxicon. 2008; 51: 1499-508

This communication reports the separation of 80 fractions from the venom of theIschnuridae scorpion Opisthacanthus cayaporum by high-performance liquidchromatography (HPLC). From these, 93 distinct components were identified byliquid chromatography/electrospray mass spectrometry (LC/ESI-MS) analysis, withmolecular weights varying from 229.2 to 61,144.0 atomic mass units. Additionally,the HPLC fractions were analyzed by matrix-assisted laser desorption/ionizationtime-of-flight mass spectrometry (MALDI-TOF-MS) which resulted in 221 distinctcomponents, among which were 52 of the 93 obtained by LC/ESI-MS. The entire setof different molecular species found (total of 262 molecular masses) has atrimodal molecular weight distribution, with 42% of the components possessing229.2-2985.3Da, 37% within the range of 3045.0-7258.6Da and 12% within the range 7458.4-9429Da. Seventeen peptides/proteins were isolated and were sequenced byEdman degradation, among which were a scorpine-like peptide (8315Da), presenting antimicrobial activity, and two phospholipase A2 with a molecular weight around14kDa. The pharmacological effects of the venom were tested on isolated rat andinsect (cockroach) nerves using the single sucrose-gap assay. The ED50 of thevenom was 1.1mg/ml in insect nerves. Venom concentrations in the order of 3mg/ml causes only 9% reduction of compound action potentials (APs) of rat nerves,suggesting that this venom is rather specific for insects. Comparative analysisof venom from male and female O. cayaporum was performed by HPLC and MALDI-TOF-MSshowing no qualitative variations, but rather quantitative differences among bothsamples.

Characterization of peptide components in the venom of the scorpion Liochelesaustralasiae (Hemiscorpiidae).

Miyashita M, Otsuki J, Hanai Y, Nakagawa Y, Miyagawa H
Toxicon. 2007; 50: 428-37

Scorpion venoms are composed of a number of neurotoxic peptides. A variety oftoxins have been isolated from the venoms of scorpions of the family Buthidae,however, little interest has been paid to non-Buthidae scorpions. In this study, we examined the toxicity of the venom of Liocheles australasiae (Hemiscorpiidae) to mice and crickets, and characterized the peptide components by HPLC and massspectrometry. Over 200 components were detected in the L. australasiae venom byLC/MS analysis, with components of molecular masses ranging from 500 to 5000 Dabeing particularly abundant. A number of peptides contained two to four disulfidebridges, which was estimated based on the mass difference after derivatization ofCys residues. A peptide having a monoisotopic molecular mass of 7781.6 Da andfour disulfide bridges was isolated from the venom. The peptide has a primarystructure similar in terms of the position of eight Cys residues to thoseobserved in several peptides found from scorpions, ticks and insects, althoughbiological roles of these peptides are unknown.