title: Evidence for a functional genetic polymorphism of the human thiosulfate sulfurtransferase (Rhodanese), a cyanide and H2S detoxification enzyme.
abstract: Rhodanese or thiosulfate sulfurtransferase (TST) is a mitochondrial matrix enzyme that plays roles in cyanide detoxification, the formation of iron-sulfur proteins and the modification of sulfur-containing enzymes. Transsulfuration reaction catalyzed by TST is also involved in H(2)S detoxification. To date, no polymorphism of the human TST gene had been reported. We developed a screening strategy based on a PCR-SSCP method to search for mutations in the 3 exons of TST and their proximal flanking regions. This strategy has been applied to DNA samples from 50 unrelated French individuals of Caucasian origin. Eleven polymorphisms consisting in seven nucleotide substitutions in non-coding regions, two silent mutations and two missense mutations were characterized. The functional consequences of the identified mutations were assessed in vivo by measurement of erythrocyte TST activity and/or in vitro using heterologous expression in Saccharomyces cerevisiae or transient transfection assay in HT29 and Caco-2 cell lines. The P(285)A variant appears to encode a protein with a 50% decrease of in vitro intrinsic clearance compared to the wild-type enzyme. Additionally, the six polymorphisms located upstream the ATG initiation codon are responsible for a significant decrease (ranging from 40% to 73%) in promoter activity of a reporter gene compared to the corresponding wild-type sequence. This work constitutes the first report of the existence of a functional genetic polymorphism affecting TST activity and should be of great help to investigate certain disorders for which impairment of CN(-) or H(2)S detoxification have been suggested to be involved.
authors.affiliation: Equipe d'Accueil EA2679, Faculté de Médecine, Pôle Recherche, Lille, France.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Billaut-Laden
authors.forename: Delphine
authors.initials: D
authors.lastname: Allorge
authors.forename: Aurélie
authors.initials: A
authors.lastname: Crunelle-Thibaut
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Rat
authors.forename: Christelle
authors.initials: C
authors.lastname: Cauffiez
authors.forename: Dany
authors.initials: D
authors.lastname: Chevalier
authors.forename: Nicole
authors.initials: N
authors.lastname: Houdret
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Lo-Guidice
authors.forename: Franck
authors.initials: F
authors.lastname: Broly
mesh_terms: D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D003486:Cyanides / Q000378:metabolism; D004252:DNA Mutational Analysis; D005260:Female; D005602:France; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D006862:Hydrogen Sulfide / Q000378:metabolism; D008297:Male; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D011110:Polymorphism, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013884:Thiosulfate Sulfurtransferase / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D044465:White People / Q000235:genetics
chemical_list: D003486:Cyanides; D013884:Thiosulfate Sulfurtransferase; D006862:Hydrogen Sulfide