IDENTIFICATION AND CHARACTERIZATION OF MAIZE FRATAXIN ISOFORMS

BUCHENSKY C.; CARRILLO, M; BUSI, M.V.; GOMEZ-CASATI, D.F

Mendoza

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2012

SAIB

Mitochondria and chloroplasts perform several processes essential for cell life. In many of these, that involve for example electron transfer, gene expression regulation and environmental sensing,participates different Fe-S proteins. Moreover, both organelles contain several components that are homologous to the bacterial or yeast Fe?S cluster assembly machinery, suggesting the presence of two biosynthetic pathways.Frataxin (FH) is a highly conserved nuclear encoded protein that has been proposed to participate as iron donor in Fe-S cluster assembly. Besides, this protein is involved in iron homeostasis, hememetabolism, ROS and REDOX control and protection against oxidative damage. However, its precise function remains unclear. This protein has been characterized in bacteria, yeast, humans and in Arabidopsis thaliana plants (AtFH). In eukaryotes, it was reported a mitochondrial localization for FH. In maize, we identified two coding sequences homologous to AtFH (ZmFH42 and ZmFH55).QPCR experiments showed that both genes are expressed mainly in young tissues. Furthermore, we cloned, purified and characterized both isoforms. Results show that at least one (ZmFH55) is afunctional protein because it attenuates Fenton reaction. Finally, confocal microscopy studies on A. thaliana protoplasts transformed with GFP-ZmFH suggest mainly a mitochondrial localization forboth proteins