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Characterization and expression analysis of genes encoding α and β carbonic anhydrases in Arabidopsis
Author(s) -
FABRE NICOLAS,
REITER ILJA M,
BECUWELINKA NOELLE,
GENTY BERNARD,
RUMEAU DOMINIQUE
Publication year - 2007
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2007.01651.x
Subject(s) - arabidopsis , carbonic anhydrase , gene isoform , subcellular localization , gene , rubisco , complementary dna , chloroplast , biochemistry , biology , cytosol , gene expression , gene family , microbiology and biotechnology , chemistry , enzyme , mutant
Carbonic anhydrases (CAs) are Zn‐containing metalloenzymes that catalyse the reversible hydration of CO 2 . We investigated the α CA and β CA families in Arabidopsis , which contain eight αCA ( AtαCA1‐8 ) and six β CA genes ( AtβCA1‐6 ). Analyses of expressed sequence tags (ESTs) from The Arabidopsis Information Resource (TAIR) database indicate that all the β CA encoding sequences, but only three of the At α CA, are expressed. Using semi‐quantitative PCR experiments, functional CA genes were more strongly expressed in green tissue, but strong expression was also found in roots for β CA3, β CA6 and α CA2. Two α CA genes were shown to respond to the CO 2 environment, while the others were unresponsive. Using the green fluorescent reporter protein gene fused with cDNA sequences coding for β CAs, we provided evidence that β CAs were targeted to specific subcellular compartments: β CA1 and β CA5 were targeted to the chloroplast, β CA2 and β CA3 to the cytosol, β CA4 to the plasma membrane and β CA6 to the mitochondria. The targeting and the pattern of gene expression suggest that CA isoforms play specific roles in subcellular compartments, tissues and organs. The data indicate that other CA isoforms than the well‐characterized β CA1 may contribute to the CO 2 transfer in the cell to the catalytic site of ribulose 1·5‐bisphosphate carboxylase/oxygenase (Rubisco).