Global Transcriptome Analysis of the Scorpion Centruroides noxius: New Toxin Families and Evolutionary Insights from an Ancestral Scorpion Species

Abstract

Scorpion venoms have been studied for decades, leading to the identification of hundreds of different toxins with medical and pharmacological implications. However, little emphasis has been given to the description of these arthropods from cellular and evolutionary perspectives. In this report, we describe a transcriptomic analysis of the Mexican scorpion Centruroides noxius Hoffmann, performed with a pyrosequencing platform. Three independent sequencing experiments were carried out, each including three different cDNA libraries constructed from RNA extracted from the whole body of the scorpion after telson removal, and from the venom gland before and after venom extraction. Over three million reads were obtained and assembled in almost 19000 isogroups. Within the telson-specific sequences, 72 isogroups (0.4% of total unique transcripts) were found to be similar to toxins previously reported in other scorpion species, spiders and sea anemones. The annotation pipeline also revealed the presence of important elements of the small non-coding RNA processing machinery, as well as microRNA candidates. A phylogenomic analysis of concatenated essential genes evidenced differential evolution rates in this species, particularly in ribosomal proteins and proteasome components. Additionally, statistical comparison of transcript abundance before and after venom extraction showed that 3% and 2% of the assembled isogroups had higher expression levels in the active and replenishing gland, respectively. Thus, our sequencing and annotation strategies provide a general view of the cellular and molecular processes that take place in these arthropods, allowed the discovery of new pharmacological and biotechnological targets and uncovered several regulatory and metabolic responses behind the assembly of the scorpion venom. The results obtained in this report represent the first high-throughput study that thoroughly describes the universe of genes that are expressed in the scorpion Centruroides noxius Hoffmann, a highly relevant organism from medical and evolutionary perspectives.

Unique diversity of the venom peptides from the scorpion Androctonus bicolor revealed by transcriptomic and proteomic analysis

“…The transcripts of NaTxs and KTxs are largely dominant, accounting for 36.9% of the total venom peptide transcripts of A. bicolor. This expression level is higher than those of Tityus stigmurus (14.8%), L. mucronatus (21.8%), and Isometrus maculatus (17.5%), but is lower than that of Centruroides noxius (54.6%), one of the most poisonous scorpions in the world [17,25,32]. It was shown that the sting of A. bicolor may cause pain, hyperemia, vomiting, swelling, restlessness and hypotension [73].…”

Scorpion Venom Gland Transcriptomics

“…In contrast to the abovementioned reports, this study did not focus on the discovery of new toxins, but rather aimed at making a comprehensive multigene-based phylogenetic analysis of arthropods. C. noxius was the second Buthid species to be analyzed with this platform (Rendón-Anaya et al 2012). In this report, the transcriptomes of resting and active (milked) venom glands were compared and contrasted to a third cDNA library obtained from RNA extracted from the body after telson removal.…”

“…So far, we have some evidence that important toxin genes might be overexpressed right after the electric milking of the venom glands (Morgenstern et al 2011;Rendón-Anaya et al 2012), but, which other factors alter these toxin profiles? It has been suggested that the length and location of introns in toxin genes could alter to some extent their expression, as observed for K + channel toxins in M. martensii Zeng et al 2012).…”

“…With the advent of high-throughput sequencing technologies, known as RNA-seq, the amount of information that can be gathered from the cDNA libraries has grown exponentially. Scorpions are not an exception, and by now, reports have emerged describing the whole transcriptome sequencing of two species using next-generation methods: the African scorpion Pandinus imperator (Roeding et al 2009) and the Mexican Centruroides noxius (Rendón-Anaya et al 2012). …”

Improved System for Constructing Bacterial cDNA Libraries From the Venom Glands of Two Iranian Scorpions

“…After, the cells grow in agar media. Finally, in isolating every clone in the library, the primary aim outlined above is obtained (5)(6)(7)(8).…”