Oxford University Press, Plant Physiology, 3(120), p. 773-778, 1999
DOI: 10.1104/pp.120.3.773
Full text: Unavailable
Abstract 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.