Effect of copper exposure on gene expression profiles in Chlamydomonas reinhardtii based on microarray analysis.
Copper is a naturally occurring trace metal with toxic properties for man and environment. It is assumed that toxicity is primarily caused by oxidative damage, generated through the production of reactive oxygen species. Copper is, however, also an essential element, which means trace amounts are necessary for biological processes to function properly. Organisms are therefore presented with the challenging problem of maintaining copper concentrations within a well-defined range to avoid stress. We exposed the green alga Chlamydomonas reinhardtii to different copper concentrations and used microarray analysis to investigate the changes in mRNA abundances and to obtain an image of the molecular mechanisms underlying copper homeostasis. The results confirm and extend upon previous findings showing that in the case of lower copper concentrations there is a change in levels of mRNA coding for alternative polypeptides which can take over the function of certain copper containing molecules so as to compensate for the lack of copper. In the case of copper toxicity, there is a strong upregulation of transcripts encoding enzymes involved in oxidative stress defense mechanisms. In both cases, there were significant changes in expression levels of transcripts coding for enzymes involved in several metabolic pathways (photosynthesis, pentose phosphate pathway, glycolysis, gluconeogenesis), in general stress response (heat shock proteins) and in intracellular proteolysis (lysosomal enzymes, proteasome components).
Jamers
An
A
Laboratory for Ecophysiology, Biochemistry and Toxicology, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium. an.jamers@ua.ac.be
Van der Ven
Karlijn
K
Moens
Lotte
L
Robbens
Johan
J
Potters
Geert
G
Guisez
Yves
Y
Blust
Ronny
R
De Coen
Wim
W
D020418:Algal Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D000704:Analysis of Variance; D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D003300:Copper / Q000032:analysis / Q000633:toxicity*; D003470:Culture Media / Q000032:analysis; D017931:DNA Primers / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression / Q000187:drug effects*; D020869:Gene Expression Profiling / Q000379:methods; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D016133:Polymerase Chain Reaction; D015203:Reproducibility of Results; D013997:Time Factors
D020418:Algal Proteins; D003470:Culture Media; D017931:DNA Primers; D003300:Copper