Open AccessHeavy-Metal Regulation of Thioredoxin Gene Expression inChlamydomonas reinhardtii
Author(s) -
Stéphane D. Lemaire,
Eliane Keryer,
Mariana Stein,
Isabelle Schepens,
Emmanuelle IssakidisBourguet,
Catherine GérardHirne,
Myroslawa MiginiacMaslow,
JeanPierre Jacquot
Publication year - 1999
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.120.3.773
Subject(s) - chlamydomonas reinhardtii , thioredoxin , cadmium , heavy metals , gene expression , gene , chlamydomonas , chlorophyceae , biology , metal , microbiology and biotechnology , chemistry , biochemistry , botany , algae , environmental chemistry , chlorophyta , organic chemistry , mutant
Heavy metals are highly toxic compounds for cells. In this report we demonstrate that the expression of Chlamydomonas reinhardtii thioredoxins (TRX)m and h is induced by heavy metals. Upon exposure of the cells to Cd and Hg, a strong accumulation of both messengers was observed. Western-blot experiments revealed that among these two TRXs, only TRX h polypeptides accumulated in response to the toxic cations. A biochemical analysis indicated that heavy metals inhibit TRX activity, presumably by binding at the level of their active site. Sequence analysis of the C. reinhardtii TRX h promoter revealed the presence of cis-acting elements related to cadmium induction. The origins and purposes of this regulation are discussed. Our data suggest, for the first time to our knowledge, a possible implication of TRXs in defense mechanisms against heavy metals.
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