Ycf1p-dependent Hg(II) detoxification in Saccharomyces cerevisiae.
In Saccharomyces cerevisiae, disruption of the YCF1 gene increases the sensitivity of cell growth to mercury. Transformation of the resulting ycf1 null mutant with a plasmid harbouring YCF1 under the control of the GAL promoter largely restores the wild-type resistance to the metal ion. The protective effect of Ycf1p against the toxicity of mercury is especially pronounced when yeast cells are grown in rich medium or in minimal medium supplemented with glutathione. Secretory vesicles from S. cerevisiae cells overproducing Ycf1p are shown to exhibit ATP-dependent transport of bis(glutathionato)mercury. Moreover, using beta-galactosidase as a reporter protein, a relationship between mercury addition and the activity of the YCF1 promoter can be shown. Altogether, these observations indicate a defence mechanism involving an induction of the expression of Ycf1p and transport by this protein of mercury-glutathione adducts into the vacuole. Finally, possible coparticipation in mercury tolerance of other ABC proteins sharing close homology with Ycf1p was investigated. Gene disruption experiments enable us to conclude that neither Bpt1p, Yor1p, Ybt1p nor YHL035p plays a major role in the detoxification of mercury.
Gueldry
Olivier
O
Laboratoire de Biochimie, Unité Mixte de Recherche CNRS-Ecole Polytechnique, Palaiseau, France.
Lazard
Myriam
M
Delort
Florence
F
Dauplais
Marc
M
Grigoras
Ioana
I
Blanquet
Sylvain
S
Plateau
Pierre
P
D018528:ATP-Binding Cassette Transporters / Q000378:metabolism* / Q000502:physiology; D001483:Base Sequence; D001965:Bromides / Q000494:pharmacology; D002455:Cell Division; D003001:Cloning, Molecular; D004137:Dinitrochlorobenzene / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005838:Genotype; D005978:Glutathione / Q000378:metabolism; D007202:Indicators and Reagents / Q000494:pharmacology; D007477:Ions; D007763:Lac Operon; D008628:Mercury / Q000494:pharmacology; D017669:Mercury Compounds / Q000494:pharmacology; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism* / Q000502:physiology; D013997:Time Factors; D001616:beta-Galactosidase / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D001965:Bromides; D004137:Dinitrochlorobenzene; D007202:Indicators and Reagents; D007477:Ions; D017669:Mercury Compounds; D029701:Saccharomyces cerevisiae Proteins; C089179:YCF1 protein, S cerevisiae; D001616:beta-Galactosidase; D008628:Mercury; D005978:Glutathione; C042720:mercuric bromide