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Evolution of complex structures: minicollagens shape the cnidarian nematocyst

2008; Elsevier BV; Volume: 24; Issue: 9 Linguagem: Inglês

10.1016/j.tig.2008.07.001

1362-4555

Charles N. David, Suat Özbek, Patrizia Adamczyk, Sebastián Meier, Barbara Pauly, Jarrod Chapman, Jung Shan Hwang, Takashi Gojobori, Thomas W. Holstein,

Marine Toxins and Detection Methods

The generation of biological complexity by the acquisition of novel modular units is an emerging concept in evolutionary dynamics. Here, we review the coordinate evolution of cnidarian nematocysts, secretory organelles used for capture of prey, and of minicollagens, proteins constituting the nematocyst capsule. Within the Cnidaria there is an increase in nematocyst complexity from Anthozoa to Medusozoa and a parallel increase in the number and complexity of minicollagen proteins. This complexity is primarily manifest in a diversification of N- and C-terminal cysteine-rich domains (CRDs) involved in minicollagen polymerization. We hypothesize that novel CRD motifs alter minicollagen networks, leading to novel capsule structures and nematocyst types. The generation of biological complexity by the acquisition of novel modular units is an emerging concept in evolutionary dynamics. Here, we review the coordinate evolution of cnidarian nematocysts, secretory organelles used for capture of prey, and of minicollagens, proteins constituting the nematocyst capsule. Within the Cnidaria there is an increase in nematocyst complexity from Anthozoa to Medusozoa and a parallel increase in the number and complexity of minicollagen proteins. This complexity is primarily manifest in a diversification of N- and C-terminal cysteine-rich domains (CRDs) involved in minicollagen polymerization. We hypothesize that novel CRD motifs alter minicollagen networks, leading to novel capsule structures and nematocyst types. simplest metazoan phylum with clear functional features of all higher metazoans, such as epithelia, basement membrane, cell junctions, and nerve cells. In addition, Cnidaria form nematocysts, an intracellular organelle unique to animals of this phylum. Anthozoa (octocorals and hexacorals) are primarily sessile marine forms. Medusozoa are divided into Hydrozoa, Scyphozoa and Cubozoa. Scyphozoa and Cubozoa are pelagic marine jellyfish. Hydrozoa are the largest and most diverse group of cnidarians. They have medusa and sessile polyp stages and are widely distributed in marine and freshwater environments. conserved cysteine motif at the N and C terminus of minicollagen molecules, which is involved in minicollagen polymerization during capsule wall formation. uniquely short collagen molecules that are major constituents of nematocyst wall and tubule structures. intracellular organelle found in all Cnidaria and used in the capture of prey. The organelle is formed in a post-Golgi vacuole in differentiating nematocytes. Explosive discharge of nematocysts is stimulated by a mechanosensory cilium (cnidocil). Nematocysts consist of a capsule and an extended tubule armed with spines. There are about 30 different morphological and functional types of nematocysts in Cnidaria. open sea zone, away from the sea bottom. The antonym is benthic, which is the zone near the seabed.