title: Genetic and immunological characterisation of a multixenobiotic resistance system in the turbot (Scophthalmus maximus).
abstract: Pleiotropic resistance driven by transport proteins constitutes a very ubiquitous protection mechanism against natural or synthetic toxic compounds. The multidrug (MDR) or multixenobiotic (MXR) system has been identified in many different species, and may be used as a biomarker for pollution assessment. Here we report the existence of a gene encoding a MXR-related protein in a benthic fish species, the turbot Scophthalmus maximus, and its constitutive expression in several tissues. A 433bp cDNA fragment has been cloned by RT-PCR. The deduced amino-acid sequence shares close to 80% homology with class I or class II mammalian MDR proteins. This cDNA corresponds to a major mRNA of 5.6 kb and encodes a protein having an apparent molecular weight of 83 kDa. Constitutive expression levels assessed by semi-quantitative RT-PCR and Western blot, revealed that the kidney and the brain, and to a lesser extent, the heart, gills and intestine, are the organs which contain the highest amount of both MXR mRNAs or proteins. This tissue specific expression suggests a role for the identified mechanism in protection against endogenous or exogenous toxic compounds.
authors.affiliation: Laboratoire d'Ecotoxicologie, UPRES EA 3222, Université du Havre, 25 rue Philippe Lebon, BP 540, 76058 Le Havre, France. renaud.tutundjian@univ-lehavre.fr
authors.forename: Renaud
authors.initials: R
authors.lastname: Tutundjian
authors.forename: J
authors.initials: J
authors.lastname: Cachot
authors.forename: F
authors.initials: F
authors.lastname: Leboulenger
authors.forename: C
authors.initials: C
authors.lastname: Minier
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D018432:Drug Resistance, Multiple / Q000235:genetics* / Q000276:immunology*; D029941:Fish Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D005412:Flatfishes / Q000235:genetics* / Q000276:immunology*; D020869:Gene Expression Profiling; D019450:Genes, MDR / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009928:Organ Specificity; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D015262:Xenobiotics / Q000494:pharmacology*
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; D015262:Xenobiotics