title: Retinoid X receptor and retinoic acid response in the marine sponge Suberites domuncula.
abstract: To date no nuclear receptors have been identified or cloned from the phylogenetically oldest metazoan phylum, the Porifera (sponges). We show that retinoic acid causes tissue regression in intact individuals of the demosponge Suberites domuncula and in primmorphs, special three-dimensional cell aggregates. Primmorphs were cultivated on a galectin/poly-L-lysine matrix in order to induce canal formation. In the presence of 1 or 50 micromol l(-1) retinoic acid these canals undergo regression, a process that is reversible. We also cloned the cDNA from S. domuncula encoding the retinoid X receptor (RXR), which displays the two motifs of nuclear hormone receptors, the ligand-binding and the DNA-binding domains, and performed phylogenetic analyses of this receptor. RXR expression undergoes strong upregulation in response to treatment with retinoic acid, whereas the expression of the sponge caspase is not increased. The gene encoding the LIM homeodomain protein was found to be strongly upregulated in response to retinoic acid treatment. These data indicate that the RXR and its ligand retinoic acid play a role in the control of morphogenetic events in sponges.
authors.affiliation: Institut für Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universität, Duesbergweg 6, D-55099 Mainz, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Wiens
authors.forename: Renato
authors.initials: R
authors.lastname: Batel
authors.forename: Michael
authors.initials: M
authors.lastname: Korzhev
authors.forename: Werner E G
authors.initials: WE
authors.lastname: Müller
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015152:Blotting, Northern; D016000:Cluster Analysis; D017523:Croatia; D018076:DNA, Complementary / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression / Q000187:drug effects*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011161:Porifera / Q000235:genetics / Q000378:metabolism*; D018168:Receptors, Retinoic Acid / Q000235:genetics* / Q000378:metabolism; D047488:Retinoid X Receptors; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014212:Tretinoin / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D018076:DNA, Complementary; D018168:Receptors, Retinoic Acid; D047488:Retinoid X Receptors; D014157:Transcription Factors; D014212:Tretinoin