Topic
Sycon raphanus
About: Sycon raphanus is a research topic. Over the lifetime, 14 publications have been published within this topic receiving 629 citations.
Papers
TL;DR: The construction of the phylogenetic tree revealed that the PTK derived from the branch including the KRSvSD kinase, revealing the first molecular approach to elucidate the origin of metazoan PTK within the PS/TK superfamily.
Abstract: The phylum Porifera (sponges) was the first to diverge from the common ancestor of the Metazoa In this study, six cDNAs coding for protein-serine/threonine kinases (PS/TKs) are presented; they have been isolated from libraries obtained from the demosponges Geodia cydonium and Suberites domuncula and from the calcareous sponge Sycon raphanus Sequence alignments of the catalytic domains revealed that two major families of PS/TK, the "conventional" (Ca(2+)-dependent) protein kinase C (PKC), the cPKC subfamily, as well as the "novel" (Ca(2+)-independent) PKC (nPKC), form two separate clusters In each cluster, the sequence from S raphanus diverges first To approach the question about the origin of protein-tyrosine kinases (PTK), which are found only in Metazoa, we analyzed two additional PS/TKs which have been cloned from S domuncula: the stress-responsive protein kinase (KRSvSD) and the protein-kinase-C-related kinase (PRKvSD) The construction of the phylogenetic tree, comprising the eight PS/TKs and the PTK cloned previously from G cydonium, revealed that the PTK derived from the branch including the KRSvSD kinase These data facilitate the first molecular approach to elucidate the origin of metazoan PTK within the PS/TK superfamily
127 citations
TL;DR: It is suggested that within the phylum Porifera, the class Hexactinellida diverged first from a common ancestor to the Calcarea and the Demospongiae, which both appeared later, and the higher invertebrates are more closely related to the calcareous sponges.
Abstract: Recent analyses of genes encoding proteins typical for multicellularity, especially adhesion molecules and receptors, favor the conclusion that all metazoan phyla, including the phylum Porifera (sponges), are of monophyletic origin. However, none of these data includes cDNA encoding a protein from the sponge class Hexactinellida. We have now isolated and characterized the cDNA encoding a protein kinase C, belonging to the C subfamily (cPKC), from the hexactinellid sponge Rhabdocalyptus dawsoni. The two conserved regions, the regulatory part with the pseudosubstrate site, the two zinc fingers, and the C2 domain, as well as the catalytic domain were used for phylogenetic analyses. Sequence alignment and construction of a phylogenetic tree from the catalytic domains revealed that the yeast Saccharomyces cerevisiae and the protozoan Trypanosoma brucei are at the base of the tree, while the hexactinellid R. dawsoni branches off first among the metazoan sequences; the other two classes of the Porifera, the Calcarea (the sequence from Sycon raphanus was used) and the Demospongiae (sequences from Geodia cydonium and Suberites domuncula were used), branch off later. The statistically robust tree also shows that the two cPKC sequences from the higher invertebrates Drosophila melanogaster and Lytechinus pictus are most closely related to the calcareous sponge. This finding was also confirmed by comparing the regulatory part of the kinase gene. We suggest, that (i) within the phylum Porifera, the class Hexactinellida diverged first from a common ancestor to the Calcarea and the Demospongiae, which both appeared later, and (ii) the higher invertebrates are more closely related to the calcareous sponges.
108 citations
TL;DR: It is concluded that the InsR-like molecules evolved in sponges prior to the "Cambrian Explosion" and contributed to the rapid appearance of the higher metazoan phyla.
Abstract: One autapomorphic character restricted to all Metazoa including Porifera (sponges) is the existence of transmembrane receptor tyrosine kinases (RTKs). In this study we screened for molecules from one subfamily within the superfamily of the insulin receptors. The subfamily includes the insulin receptors (InsR), the insulin-like growth factor I receptors, and the InsR-related receptors-all found in vertebrates-as well as the InsR-homolog from Drosoph- ila melanogaster. cDNAs encoding putative InsRs were isolated from the hexactinellid sponge Aphrocallistes vas- tus, the demosponge Suberites domuncula, and the calcar- eous sponge Sycon raphanus. Phylogenetic analyses of the catalytic domains of the putative RTKs showed that the sponge polypeptides must be grouped with the InsRs. The relationships revealed that all sponge sequences fall into one branch of this group, whereas related sequences from mam- mals (human, mouse, and rat), insects and molluscs, and polypeptides from one cephalochordate, fall together into a second branch. We have concluded that (i) the InsR-like
92 citations
TL;DR: The metazoan essentials have been defined by analyzing and comparing the sponge sequences with the related sequences from the metazoans Homo sapiens, Caenorhabditis elegans and Drosophila melanogaster, the fungus Saccharomyces cerevisiae and the plant Arabidopsis thaliana.
67 citations
TL;DR: The results reveal an unexpected diversification of homeobox genes in S. raphanus, which suggests that diversifying of the NK-2 class occurred early in metazoan history.
64 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 1 |
| 2014 | 2 |
| 2013 | 1 |
| 2012 | 1 |
| 2001 | 1 |
| 2000 | 1 |