title: Ascidians as a vertebrate-like model organism for physiological studies of Rho GTPase signaling.
abstract: GTPases of the Rho family are evolutionarily conserved proteins that control cell shape dynamics during physiological processes as diverse as cell migration and polarity, axon outgrowth and guidance, apoptosis and phagocytosis. In mammals, 18 Rho proteins are distributed in 7 subfamilies. Rho, Rac and Cdc42 are the best-characterized ones, benefiting from the use of worm and drosophila, which only express these 3 subfamilies. An additional model would therefore help understand the physiological role of other mammalian subfamilies. We identified in genome databases the complete Rho family of two ascidians, Ciona intestinalis and Ciona savignyi, and showed that these families contain single ancestors of most mammalian Rho subfamilies. In Ciona intestinalis, all Rho genes are expressed and display specific developmental variations of mRNA expression during tadpole formation. Although C. intestinalis expresses five additional Rac compared to the closely related Ciona savignyi, only two appeared fully active in functional assays. Last, we identified in Ciona intestinalis database more than 50 Rho regulators (RhoGEFs and RhoGAPs) and 20 effector targets, whose analysis further supports the notion that Rho signaling components are of comparable complexity in mammals and ascidians. Since the tadpole of ascidians combines vertebrate-like developmental features with reduced cell number, particularly adapted to evolutionary and developmental biology studies, our data advocate this model for physiological studies of Rho signaling pathways.
authors.affiliation: CRBM, CNRS-FRE2593, IFR122, 1919, route de Mende, 34293 Montpellier cedex 5, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Philips
authors.forename: Marion
authors.initials: M
authors.lastname: Blein
authors.forename: Agnès
authors.initials: A
authors.lastname: Robert
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Chambon
authors.forename: Stephen
authors.initials: S
authors.lastname: Baghdiguian
authors.forename: Mylène
authors.initials: M
authors.lastname: Weill
authors.forename: Philippe
authors.initials: P
authors.lastname: Fort
mesh_terms: D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D048429:Cell Size / Q000235:genetics / Q000502:physiology; D002938:Ciona intestinalis / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D003001:Cloning, Molecular; D019295:Computational Biology; D030541:Databases, Genetic; D004625:Embryo, Nonmammalian / Q000378:metabolism; D005347:Fibroblasts / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D020690:GTPase-Activating Proteins / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D023061:Gene Order / Q000235:genetics; D015698:Genomic Library; D049452:Green Fluorescent Proteins; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics; D007814:Larva / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D008856:Microscopy, Fluorescence; D023421:Models, Animal; D008969:Molecular Sequence Data; D010802:Phylogeny; D011494:Protein Kinases / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D064067:Rho Guanine Nucleotide Exchange Factors; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000502:physiology*; D014561:Urochordata / Q000201:enzymology / Q000235:genetics* / Q000502:physiology; D020764:cdc42 GTP-Binding Protein / Q000235:genetics; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000502:physiology; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D000199:Actins; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D008164:Luminescent Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D064067:Rho Guanine Nucleotide Exchange Factors; C085379:rho GTPase-activating protein; D049452:Green Fluorescent Proteins; D011494:Protein Kinases; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins