title: Modulation of myb gene expression in sponges by retinoic acid.
abstract: We demonstrate that the cells of the sponge Geodia cydonium are equipped with the basic elements required for a retinoic acid (RA)-dependent response pathway; RA was identified and quantitated, the cellular RA-binding protein (CRABP) was detected and the nuclear RA receptor (RAR) was found. In the isolated cell system the level of CRABP, but not of RAR, is strongly induced after incubating the cells for 10h with the homologous aggregation factor. In induced cells incubation with 0.3 microM RA results in a strong down-regulation of the c-myb (or c-myb-related) proto-oncogene (M(r) 63,000; mRNA 3.3 kb). We postulate that this pathway is also functionally active and that RA acts as a natural morphogen.
authors.affiliation: Institute für Physiologische Chemie, Universität, Mainz, Germany.
authors.forename: H K
authors.initials: HK
authors.lastname: Biesalski
authors.forename: G
authors.initials: G
authors.lastname: Doepner
authors.forename: G
authors.initials: G
authors.lastname: Tzimas
authors.forename: V
authors.initials: V
authors.lastname: Gamulin
authors.forename: H C
authors.initials: HC
authors.lastname: Schröder
authors.forename: R
authors.initials: R
authors.lastname: Batel
authors.forename: H
authors.initials: H
authors.lastname: Nau
authors.forename: W E
authors.initials: WE
authors.lastname: Müller
mesh_terms: D000818:Animals; D001483:Base Sequence; D002338:Carotenoids / Q000032:analysis; D002352:Carrier Proteins / Q000032:analysis; D004247:DNA / Q000096:biosynthesis; D005786:Gene Expression Regulation / Q000187:drug effects*; D008969:Molecular Sequence Data; D009857:Oncogenes; D011161:Porifera / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D020598:Proto-Oncogene Proteins c-myb; D018168:Receptors, Retinoic Acid; D012176:Retinoids / Q000032:analysis; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D002352:Carrier Proteins; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D018168:Receptors, Retinoic Acid; D012176:Retinoids; D002338:Carotenoids; D014212:Tretinoin; D004247:DNA