title: Increased expression of integrin and receptor tyrosine kinase genes during autograft fusion in the sponge Geodia cydonium.
abstract: Recently cDNAs coding for cell surface molecules have been isolated from sponges. The molecules for alpha-integrin, galectin, and receptor tyrosine kinase (RTK), obtained from the marine sponge, Geodia cydonium, have been described earlier. In the present study also the cDNA for one putative beta-integrin has been identified from G. cydonium. The deduced aa sequence comprises the characteristic signatures, found in other metazoan beta-integrin molecules; the estimated size is 95,215 Da. To obtain first insights into the molecular events which proceed during autograft fusion, the expressions of these genes were determined on transcriptional and translational level. The cDNAs as well as antibodies raised against the recombinant sponge proteins alpha-integrin, RTK and galectin were used and Northern blot experiments and immunocytochemical analyses have been performed. The results show that transcription of the two subunits of an integrin receptor as well as of the RTK are strongly upregulated after grafting; levels of > 10-fold have been determined in the fusion zone of the grafts after a 10 days incubation. Immunofluorescence studies of sections through the fusion zone support these data. In contrast the transcription of the gene encoding galectin is drastically downregulated after grafting. In a parallel series of experiments the level of the heat-shock protein-70 was determined and it was found that it remained unchanged after grafting. We conclude that integrin subunits and the RTK molecule are involved in self-self recognition of sponge.
authors.affiliation: Institut für Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universität, Mainz, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Wimmer
authors.forename: B
authors.initials: B
authors.lastname: Blumbach
authors.forename: B
authors.initials: B
authors.lastname: Diehl-Seifert
authors.forename: C
authors.initials: C
authors.lastname: Koziol
authors.forename: R
authors.initials: R
authors.lastname: Batel
authors.forename: R
authors.initials: R
authors.lastname: Steffen
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; D003001:Cloning, Molecular; D018076:DNA, Complementary; D015870:Gene Expression; D006801:Humans; D019012:Integrin beta1 / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011161:Porifera / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013194:Staining and Labeling
chemical_list: D018076:DNA, Complementary; D019012:Integrin beta1; D020794:Receptor Protein-Tyrosine Kinases