46 / 2021-10-09 22:01:12

Transcriptome Sequencing of the Pale anemones (Exaiptasia diaphana) reveals Functional Peptide Gene Resources of Sea Anemone

sea anemone; Exaiptasia diaphana; transcriptomics; toxins; proteins

Abstract:

Background: Sea anemone venom contains a complex and diverse arsenal of peptides and proteins of pharmacological and biotechnological interest, however, only venom from a few sea anemone species has been explored from a global perspective to date. This study aims to realize large-scale discovery of protein and peptide toxin sequences from different developmental stages of the sea anemone Exaiptasia diaphana by high-throughput transcriptome sequencing.

Results: Using high-throughput transcriptome sequencing, 148, 185, 166 putative protein and toxins precursors, respectively, were identified from the Small, Middle, and Big datasets from three body-sized Exaiptasia diaphana. A total of 534 putative protein and peptide toxin sequences were identified and assigned to 75 known superfamilies, in which most of the protein components corresponded to metalloproteases, pancreatic lipase-related protein like, chymotrypsinogen like, collagen, and G-protein coupled receptor, and the peptide components corresponded to ShKT domain, Kunitz-type, thrombin, defensin-like, and insulin-like peptide.

The top 10 protein and peptide toxins (with the highest RPKM values) were selected from each of the datasets, and ShKT domain peptide, Gastric triacylglycerol lipase, CYP17, and C-type lectin were expressed in three different developmental stages of sea anemone. Interestingly, it is worth noting that ShKT domain peptide was the dominant expression and their function is to prey capture, defense and intraspecific competition. In addition, the expression level of collagen was the highest in the middle development stage of sea anemone, and it was still relatively high in the mature stage. The high expression of collagen may be related to the adhesion ability of sea anemone.

Conclusion: Our data provided a functional peptide gene resources and the previously unrecognized changes in gene transcription from the sea anemone Exaiptasia diaphana at different developmental stages. This study therefore provides a valuable high-throughput method to obtain the resources of sea anemone protein and peptide, and lays a foundation for further targeted research on the diversity and pharmacological effects of sea anemone toxins.