Characterization of Arabidopsis thaliana genes encoding functional homologues of the yeast metal chaperone Cox19p, involved in cytochrome c oxidase biogenesis

CAROLINA V. ATTALLAH, ELINA WELCHEN, CLAIRE PUJOL, GERALDINE BONNARD, DANIEL H. GONZALEZ

PLANT MOLECULAR BIOLOGY

SPRINGER

Lugar: Zurich; Año: 2007 vol. 65 p. 343 - 355

0167-4412

The Arabidopsis thaliana genome contains twonearly identical genes which encode proteins showingsimilarity with the yeast metal chaperone Cox19p, involvedin cytochrome c oxidase biogenesis. One of these genes(AtCOX19-1) produces two transcript forms that arise froman alternative splicing event and encode proteins withdifferent N-terminal portions. Both AtCOX19 isoforms areimported into mitochondria in vitro and are found attachedto the inner membrane facing the intermembrane space.The smaller AtCOX19-1 isoform, but not the larger one, isable to restore growth on non-fermentable carbon sourceswhen expressed in a yeast cox19 null mutant. AtCOX19transcript levels increase by treatment with copper orcompounds that produce reactive oxygen species. Youngroots and anthers are highly stained in AtCOX19-1::GUSplants. Expression in leaves is only observed when cuts areproduced, suggesting an induction by wounding. Infectionof plants with the pathogenic bacterium Pseudomonassyringae pv. tomato also induces AtCOX19 gene expres-sion. The results suggest that AtCOX19 genes encodefunctional homologues of the yeast metal chaperone.Induction by biotic and abiotic stress factors may indicate arelevant role of this protein in the biogenesis of cytochromec oxidase to replace damaged forms of the enzyme or amore general role in the response of plants to stress.