title: Characterization and transcription studies of a phytochelatin synthase gene from the solitary tunicate Ciona intestinalis exposed to cadmium.
abstract: The major thiol-containing molecules involved in controlling the level of intracellular ROS in eukaryotes, acting as a nonenzymatic detoxification system, are metallothioneins (MTs), glutathione (GSH) and phytochelatins (PCs). Both MTs and GSH are well-known in the animal kingdom. PC was considered a prerogative of the plant kingdom but, in 2001, a phytochelatin synthase (PCS) gene was described in the nematode Caenorhabditis elegans; additional genes encoding this enzyme were later described in the earthworm Eisenia fetida and in the parasitic nematode Schistosoma mansoni but scanty data are available, up to now, for Deuterostomes. Here, we describe the molecular characteristics and transcription pattern, in the presence of Cd, of a PCS gene from the invertebrate chordate Ciona intestinalis, a ubiquitous solitary tunicate and demonstrate the presence of PCs in tissue extracts. We also studied mRNA localization by in situ hybridization. In addition, we analyzed the behavior of hemocytes and tunic cells consequent to Cd exposure as well as the transcription pattern of the Ciona orthologous for proliferating cell nuclear antigen (PCNA), usually considered a proliferation marker, and observed that cell proliferation occurs after 96h of Cd treatment. This matches the hypothesis of Cd-induced cell proliferation, as already suggested by previous data on the expression of a metallothionein gene in the same animal.
authors.affiliation: Department of Biology, University of Padova, Padova, Italy; Department of Biological, Chemical, Pharmaceutical Science and Technology, University of Palermo, Palermo, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Franchi
authors.affiliation: Department of Biology, University of Padova, Padova, Italy.
authors.forename: Ester
authors.initials: E
authors.lastname: Piccinni
authors.affiliation: Department of Biology, University of Padova, Padova, Italy; Institute for Evolution and Biodiversity, Westfälische Wilhelms-Universität, Münster, Germany.
authors.forename: Diana
authors.initials: D
authors.lastname: Ferro
authors.affiliation: Department of Woman and Child Health, University of Padova, Padova, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Basso
authors.affiliation: CRIBI Biotechnology Centre, University of Padova, Padova, Italy; Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Spolaore
authors.affiliation: Department of Biology, University of Padova, Padova, Italy. Electronic address: gianfranco.santovito@unipd.it.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Santovito
authors.affiliation: Department of Biology, University of Padova, Padova, Italy.
authors.forename: Loriano
authors.initials: L
authors.lastname: Ballarin
mesh_terms: D000595:Amino Acid Sequence; D019881:Aminoacyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D002104:Cadmium / Q000032:analysis / Q000633:toxicity*; D002938:Ciona intestinalis / Q000737:chemistry / Q000145:classification / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D023061:Gene Order; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium; D019881:Aminoacyltransferases; C093784:glutathione gamma-glutamylcysteinyltransferase
keywords: Ascidians; Cadmium; Cell proliferation; Ciona intestinalis; Phytochelatin synthase