Gene duplications are extensive and contribute significantly to the toxic proteome of nematocysts isolated from Acropora digitifera (Cnidaria: Anthozoa: Scleractinia)

Autor(es):Mostrar menos -

Gacesa, Ranko ^[1] ; Chung, Ray ^[2] ; Dunn, Simon R. ^[3] ; Weston, Andrew J. ^[4] ; Jaimes-Becerra, Adrian ^[5] ; Marques, Antonio C. ^{[5, 6]} ; Morandini, Andre C. ^[5] ; Hranueli, Daslav ^[7] ; Starcevic, Antonio ^[7] ; Ward, Malcolm ^[2] ; Long, Paul F. ^{[1, 8, 9, 10]}

Afiliação do(s) autor(es)

^[1] Kings Coll London, Inst Pharmaceut Sci, London SE1 9NH - England

^[2] Kings Coll London, Prote Facil, Inst Psychiat Psychol & Neurosci, London SE5 8AF - England

^[3] Univ Queensland, Sch Biol Sci, Coral Reefs Ecosyst Lab, St Lucia, Qld 4072 - Australia

^[4] UCL Sch Pharm, Mass Spectrometry Lab, London WC1N 1AX - England

^[5] Univ Sao Paulo, Inst Biociencias, Dept Zool, BR-05508090 Sao Paulo, SP - Brazil

^[6] Univ Sao Paulo, Ctr Biol Marinha, BR-11600000 Sao Sebastiao - Brazil

^[7] Univ Zagreb, Fac Food Technol & Biotechnol, Sect Bioinformat, Dept Biochem Engn, Zagreb 10000 - Croatia

^[8] Univ Sao Paulo, Fac Ciencias Farmaceut, BR-05508000 Sao Paulo, SP - Brazil

^[9] Kings Coll London, Dept Chem, London WC2R 2LS - England

^[10] Kings Coll London, Brazil Inst, London WC2R 2LS - England

• Tipo de documento: Artigo Científico
• Fonte: BMC Genomics; v. 16, OCT 13 2015.
• Citações Web of Science: 16

Resumo

Background: Gene duplication followed by adaptive selection is a well-accepted process leading to toxin diversification in venoms. However, emergent genomic, transcriptomic and proteomic evidence now challenges this role to be at best equivocal to other processess. Cnidaria are arguably the most ancient phylum of the extant metazoa that are venomous and such provide a definitive ancestral anchor to examine the evolution of this trait. Methods: Here we compare predicted toxins from the translated genome of the coral Acropora digitifera to putative toxins revealed by proteomic analysis of soluble proteins discharged from nematocysts, to determine the extent to which gene duplications contribute to venom innovation in this reef-building coral species. A new bioinformatics tool called HHCompare was developed to detect potential gene duplications in the genomic data, which is made freely available (https://github.com/rgacesa/HHCompare). Results: A total of 55 potential toxin encoding genes could be predicted from the A. digitifera genome, of which 36 (65 %) had likely arisen by gene duplication as evinced using the HHCompare tool and verified using two standard phylogeny methods. Surprisingly, only 22 % (12/55) of the potential toxin repertoire could be detected following rigorous proteomic analysis, for which only half (6/12) of the toxin proteome could be accounted for as peptides encoded by the gene duplicates. Biological activities of these toxins are dominatedby putative phospholipases and toxic peptidases. Conclusions: Gene expansions in A. digitifera venom are the most extensive yet described in any venomous animal, and gene duplication plays a significant role leading to toxin diversification in this coral species. Since such low numbers of toxins were detected in the proteome, it is unlikely that the venom is evolving rapidly by prey-driven positive natural selection. Rather we contend that the venom has a defensive role deterring predation or harm from interspecific competition and overgrowth by fouling organisms. Factors influencing translation of toxin encoding genes perhaps warrants more profound experimental consideration. (AU)

• Processo FAPESP: 10/50174-7 - Sistemática, ciclo de vida e padrões reprodutivos de medusas (Cnidaria: Medusozoa: Cubozoa e Scyphozoa) na Baixada Santista (São Paulo, Brasil): biodiversidade marinha
• Beneficiário: André Carrara Morandini
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Regular
• Processo FAPESP: 11/50242-5 - Dimensões da vida marinha: padrões e processos de diversificação em cnidários planctônicos e bentônicos
• Beneficiário: Antonio Carlos Marques
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático