title: Molecular evolution of the metazoan extracellular matrix: cloning and expression of structural proteins from the demosponges Suberites domuncula and Geodia cydonium.
abstract: One crucial event during evolution to multicellularity was the development of either direct cell-cell contact or indirect interaction via extracellular matrix (ECM) molecules. The identification of those polypeptides provides conclusive data on the phylogenetic relationship of metazoan phyla and helps us to understand the position of the Metazoa among the other kingdoms. Recently it became evident that the ECM of sponges is amazingly complex; it is composed of fibrous molecules, e.g., collagen, and their corresponding receptors, which are highly similar to those existing in other metazoan phyla. While these data already support the view of monophyly of Metazoa, additional studies are required to understand whether these molecules, which are similar in their primary sequence, also have the same function throughout the metazoan kingdom. In the present study we identified the ligand for one of the autopomorphic characters of Metazoa, the single-transmembrane receptor protein with the receptor tyrosine kinase (RTK) from G. cydonium, as an example: the putative mucus-like protein from G. cydonium. This protein was upregulated during autograft fusion in the homologous system with kinetics similar to those of the RTK. Additionally, a cDNA was isolated from S. domuncula whose deduced polypeptide displays a high sequence similarity to dermatopontin, an ECM molecule found exclusively in Metazoa. Furthermore, it is documented that expression of the fibrous ECM molecule collagen is regulated by the characteristic metazoan morphogens myotrophin and endothelial monocyte-activating polypeptide. These data indicate that the ECM of sponges is not an unstructured ground substance but provides the basis for integrated cell communication.
authors.affiliation: Institut für Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universität, Duesbergweg 6, D-55099 Mainz, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Schütze
authors.forename: A
authors.initials: A
authors.lastname: Skorokhod
authors.forename: I M
authors.initials: IM
authors.lastname: Müller
authors.forename: W E
authors.initials: WE
authors.lastname: Müller
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000494:pharmacology; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000494:pharmacology; D002449:Cell Aggregation / Q000187:drug effects; D011508:Chondroitin Sulfate Proteoglycans; D003001:Cloning, Molecular; D003094:Collagen / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D019143:Evolution, Molecular; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D015870:Gene Expression; D006133:Growth Substances / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D010802:Phylogeny; D011161:Porifera / Q000166:cytology / Q000187:drug effects / Q000235:genetics*; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D011994:Recombinant Proteins / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D014182:Transplantation, Autologous
chemical_list: D002352:Carrier Proteins; D015815:Cell Adhesion Molecules; D011508:Chondroitin Sulfate Proteoglycans; D018076:DNA, Complementary; C082019:DPT protein, human; D016326:Extracellular Matrix Proteins; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D011994:Recombinant Proteins; C445899:mucus-like protein, Geodia cydonium; C065700:myotrophin; D003094:Collagen; D020794:Receptor Protein-Tyrosine Kinases