CLUSTERED GENES WITHIN THE GENOME OF ARABIDOPSIS-THALIANA ENCODING PECTIN METHYLESTERASE-LIKE ENZYMES

We focused our attention on the isolation and regulation of genes enco ding for pectin methylesterase (PME) isoenzymes in Arabidopsis thalian a (At). The present data reports the identification of two PME-like ge nes, named AtPME1 and AtPME2, that are closely linked in the At genome . These genes possess different structural organisations. While all hi gher plant PME characterised so far possess an intron at a similar loc ation relative to their coding sequence, AtPME2 shows an additional in tron whose presence within other higher plant PME-like genes has not b een previously reported. Sequence comparison of the N-terminal region suggests that the secretory pathways of the putative AtPME1 and AtPME2 isoforms are different, and that this region may contribute to specif y a biological function to each isoform. Moreover, phylogenetic analys is reflects the possible existence of functional groups of PME isoform s in higher plant species that seem to have been conserved during evol ution.