IJUP08 - Universidade do Porto

Computational Analisys of Cynara cardunculus L. Cardosins
Pomoters
Alberto M. Pessoa 1 , Jorge Teixeira 1 and José Pissarra 1
1 Department of Botany, School of Sciences, University of Porto, Portugal
Cardosins are aspartic proteinases from Cynara cardunculus L., a plant used to act as a
milk-clotter for the manufacture of cheese. To further understand the role of these
proteinases in the plant and how the transcriptional regulation occurs, the promoter regions
from 4 Cardosin genes were analysed and compared in silico. The promoter region of the
Cardosins A-like (A, C and D) and B, previously isolated and sequenced, were analysed
using PlantCARE (a database of plant cis-acting regulatory elements, enhancers and
repressors). Perl scripts were used to parse the reports obtained from PlantCARE for each
Cardosin sequence and to sort and format the results, so that they could be displayed on
pDraw32 (Acaclone Software), for easy interpretation. The data was also converted into a
Microsoft® Excel spreadsheet, using a similar procedure, in order to assemble charts
illustrative of the TATA Box motif distribution along the sequences. The plausibility of the
results was then verified by comparing the set of motifs obtained for each of the cardosins
with previous studies. The analysis with PlantCARE revealed that Cardosin B has the least
variety of cis-acting elements, having one exclusive light responsive element and sharing 4
motifs with the Cardosins A-like (high transcription levels conferring element, MeJAresponsiveness
involved element and a MYB binding site involved in droughtinducibility).
Cardosins A-like yielded a greater variety of results, having in common 3
motifs: abscisic acid responsiveness and light responsiveness involved elements, and the
MYB binding site also present in Cardosin B. However, the analysis revealed distinct
features on their promoters: Cardosin A – the presence of a heat stress responsiveness
involved element and the lack of light responsive elements; Cardosin C – the presence of
an ethylene-responsive element, and 3 different light responsive elements, while no
anaerobic induction, MeJA-responsiveness and endosperm expression involved elements
were detected; Cardosin D – the presence of an exclusive light responsive element and the
lack of high transcription levels conferring element and circadian control involved element.
The TATA Box motif distribution along the sequences was also analysed and showed that
the TATA box is likely to be in a distinct position, being further upstream from the ATG
codon in Cardosin B promoter, when compared to the Cardosins A-like promoters. These
results suggest that, apart from being similar, the promoters of the 4 Cardosins may have
different metabolic sensitivities. Therefore, their differential expression and detection
could be possible. These observations are being studied by promoter fusions to reporter
genes.
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