CHARACTERIZATION OF THE PROMOTER REGION OF A CYTOCHROME C GENE FROM SUNFLOWER

AGUSTÍN ARCE; FEDERICO ARIEL; RAQUEL CHAN

Pinamar

Congreso; XLI Reunión de SAIB; 2005

SAIB

  Cytochorme c is a small nuclear encoded hemoprotein that participates in mitochondrial electron transport chain. In a previous work we have reported that at least two genes encoding this protein are present in the sunflower genome. Northern blot analysis and in situ hybridization have indicated that cyt c is primarily expressed in flowers and roots. An 856 bp DNA fragment corresponding to cyt c promoter region has been isolated by inverse PCR and its sequence determined. In silico analysis reveals putative binding sites for transcription factors and a Telo box motif. To gain insight into the segments/boxes responsible of its expression, we have cloned the entire and serial deletions of this cyt c promoter region fused to the gus reporter gene, and transformed Arabidopsis thaliana plants with them. Histochemical analysis of transgenic plants indicate that the whole fragment directs expression in anthers, root tips, nascent lateral roots and vascular tissue from hypocotyls and roots and includes a repressor binding site. Shorter fragments direct expression also in leaves vascular tissues, cotyledons and sepals while pollinic sacs staining disappeares. The results indicate that tissue specific expression is directed by this promoter. We were able to detect regions responsible for this expression. Conservation and divergence between species of active cis elements will be presented and discussed.