ANALYSIS OF THE PROMOTER REGIONS OF GENES ENCODING ARABIDOPSIS CYTOCHROME C OXIDASE SUBUNITS 6a AND 6b

MUFARREGE E, CURI G, GONZÁLEZ D.

Pinamar-Buenos Aires, Argentina

Congreso; XLI Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB); 2005

Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB)

Cytochrome c oxidase (COX) is a multimeric complex composedof several subunits, three of them encoded by the mitochondrial genome and the rest encoded by the nuclear genome. In plants, there are at least 4 subunits encoded in the nuclear genome: COX5b, COX5c, COX6a and COX6b. In this work, we analyzed the expression patterns driven by the promoter regions of the Arabidopsis genes COX6a, COX6b1, COX6b2 and COX6b3. To perform this analysis, we transformed plants with the gus gene under the control of the respective sequences and analyzed GUSenzymatic activity by histochemical assays. COX6b1 promoter sequences directed GUS activity in cotyledon and leaf veins and hydathodes, trichomes, pollen grains, the stigma and in developing seeds. In COX6b2 lines, expression was detected in roots, cotyledon and leaf veins, hypocotyl vascular bundle, and in the shoot apical meristem and pollen grains. Plant lines that contained COX6b3 promoter sequences produced similar expression patterns than COX6b2 lines. Notably, plants that contained the COX6a promoter/ gus fusion, showed GUS activity only in pollen grains. The results indicate that, while all genes show expression in pollen, COX6b promoters have evolved to produce differential expression patterns in other parts of the plant.