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Functional complementation of an oxa1 − yeast mutation identifies an Arabidopsis thaliana cDNA involved in the assembly of respiratory complexes
Author(s) -
Hamel Patrice,
Sakamoto Wataru,
Wintz Henri,
Dujardin Geneviève
Publication year - 1997
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1997.12061319.x
Subject(s) - complementation , arabidopsis thaliana , complementary dna , genetics , biology , yeast , mutation , arabidopsis , gene , computational biology , mutant
The nuclear gene OXA1 is essential for respiratory growth in yeast. It codes for a chaperon‐like protein, and has pleiotropic effects on the assembly of cytochrome c oxidase and ATP synthase of the mitochondrial respiratory chain. To study respiratory complex formation in plants, we have cloned a homolog of the yeast oxa1 − in Arabidopsis thaliana , OXA1At , by functional complementation of a yeast oxa1 − mutant. OXA1At is a single copy gene and appears to be constitutively expressed in A. thaliana . Although OXA1At encodes a protein sharing only 30% amino acid identity with the yeast Oxa1 protein, hydrophobic domains likely corresponding to trans ‐membrane domains are strictly conserved. Cytochrome spectra and measurements of respiratory activities show that replacement of the yeast Oxa1 protein with the A. thaliana homolog leads to correct assembly and activity of cytochrome c oxidase, but to partial restoration of ATPase activity. Our results suggest that the Oxa1At protein is essential for the respiratory complex assembly in A. thaliana , and that genes involved in mitochondrial multiprotein complex formation can be conserved between plants and other organisms.