Comparison of the Venom Peptides and Their Expression in Closely Related Conus Species: Insights into Adaptive Post-speciation Evolution of Conus Exogenomes.
Bottom Line: In this study, the sequences and expression levels of conotoxins from several specimens of two closely related worm-hunting species, Conus tribblei and Conus lenavati, were compared through transcriptome analysis.Comparison of the interspecific expression patterns of conopeptides at the superfamily level resulted in the discovery of both conserved as well as species-specific expression patterns, indicating divergence in the regulatory network affecting conotoxin gene expression.Comparison of the transcriptomes of the individual snails revealed that each specimen produces a distinct set of highly expressed conopeptides, reflecting the capability of individual snails to fine-tune the composition of their venoms.
Affiliation: Marine Science Institute, University of the Philippines-Diliman, Quezon City, Philippines.Show MeSH
Mentions: A total of 100 unique putative conopeptide precursors belonging to 39 gene superfamilies were identified in the tribblei conopeptide data set whereas the lenavati conopeptide data set contained 132 novel putative conopeptide precursors that were classified into 40 gene superfamilies (fig. 2a). A total of 55 conopeptides in the tribblei conopeptide data set were previously discovered in C. tribblei (accession GCJM00000000 in DDBJ/EMBL/GenBank; Barghi et al. 2015), whereas the rest of the identified conopeptides were new. The majority of the identified conopeptides was classified into the known gene superfamilies (fig. 2a). Moreover, some new conopeptide groups indentified in recent transcriptome studies of the Conus venom duct were also discovered (fig. 2a); several sequences of the tribblei and lenavati conopeptide data sets showed high similarity to SF-mi2 and SF-mi4 in Conus miles (Jin et al. 2013), R, W, and Y2 in Conus marmoreus (Lavergne et al. 2013), U superfamily in Conus victoriae (Robinson et al. 2014), and A-like, G-like, N-like, Y2-like, and SF-01 groups in C. tribblei (Barghi et al. 2015) (supplementary fig. S1, Supplementary Material online). In addition, conopeptides with signal region PID values below the threshold for any conopeptide gene superfamily were classified into conopeptide groups SF-02 to SF-06 (fig. 3). Furthermore, seven putative conopeptides in the tribblei conopeptide data set and five conopeptides in the lenavati conopeptide data set showed similarity to the “divergent” superfamilies: Divergent MKFPLLFISL, divergent M–-L-LTVA, divergent MSTLGMTLL-, and divergent MSKLVILAVL (fig. 2a). Divergent superfamilies refer to the conopeptides identified in early divergent species, Conus californicus and Conus distans. The conopeptide sequences identified in C. tribblei and C. lenavati are shown in supplementary figure S1, Supplementary Material online.Fig. 2.—
Affiliation: Marine Science Institute, University of the Philippines-Diliman, Quezon City, Philippines.