Evolutionary Analysis of Cystatins of Early-Emerging Metazoans Reveals a Novel Subtype in Parasitic Cnidarians

Biology

Ashlie Hartigan¹  JerriL. Bartholomew²  StephenD. Atkinson²  Oswaldo Palenzuela³  AstridS. Holzer⁴  Amparo Picard-Sánchez⁴  Jiří Kyslík⁴  Gema Alama-Bermejo⁴  Pavla Bartošová-Sojková⁴  MarcNicolas Faber⁵  JasonW. Holland⁵ 

[1] Department of Life Sciences, Natural History Museum, London SW7 5BD, UK;Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA;Fish Pathology Group, Instituto de Acuicultura Torre de la Sal (IATS-CSIC), 12595 Castellón, Spain;Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice, Czech Republic;Scottish Fish Immunology Research Centre, Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 3UU, UK;

关键词: cysteine protease inhibitor;    stefin;    signal peptide;    parasite;    phylogenetic analysis;    diversification;   

DOI  :  10.3390/biology10020110

来源: DOAJ

【 摘 要 】

The evolutionary aspects of cystatins are greatly underexplored in early-emerging metazoans. Thus, we surveyed the gene organization, protein architecture, and phylogeny of cystatin homologues mined from 110 genomes and the transcriptomes of 58 basal metazoan species, encompassing free-living and parasite taxa of Porifera, Placozoa, Cnidaria (including Myxozoa), and Ctenophora. We found that the cystatin gene repertoire significantly differs among phyla, with stefins present in most of the investigated lineages but with type 2 cystatins missing in several basal metazoan groups. Similar to liver and intestinal flukes, myxozoan parasites possess atypical stefins with chimeric structure that combine motifs of classical stefins and type 2 cystatins. Other early metazoan taxa regardless of lifestyle have only the classical representation of cystatins and lack multi-domain ones. Our comprehensive phylogenetic analyses revealed that stefins and type 2 cystatins clustered into taxonomically defined clades with multiple independent paralogous groups, which probably arose due to gene duplications. The stefin clade split between the subclades of classical stefins and the atypical stefins of myxozoans and flukes. Atypical stefins represent key evolutionary innovations of the two parasite groups for which their origin might have been linked with ancestral gene chimerization, obligate parasitism, life cycle complexity, genome reduction, and host immunity.

【 授权许可】

Unknown