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Báo cáo khoa học: The three typical aspartic proteinase genes of Arabidopsis thaliana are differentially expressed

Genomic sequencing has identified three different typical plant aspartic proteinases in the genome ofArabidopsis thaliana, named Pasp-A1, A2 and A3. A1 is identical to a cDNA we had previously isolated and the two others pro-duceproteins 81and63%identical to that predictedprotein. Sequencing of the aspartic proteinase protein purified from Arabidopsisseeds showed that the peptides are derived from two of these genes, A1 and A2. | Eur. J. Biochem. 269 4675-4684 2002 FEBS 2002 doi 10.1046 j.1432-1033.2002.03168.x The three typical aspartic proteinase genes of Arabidopsis thaliana are differentially expressed Xia Chen Joanne E. Pfeil and Susannah Gal Department of Biological Sciences The State University of New York at Binghamton Binghamton NY USA Genomic sequencing has identified three different typical plant aspartic proteinases in the genome of Arabidopsis thaliana named Pasp-A1 A2 and A3. A1 is identical to a cDNA we had previously isolated and the two others produce proteins 81 and 63 identical to that predicted protein. Sequencing of the aspartic proteinase protein purified from Arabidopsis seeds showed that the peptides are derived from two of these genes A1 and A2. Using gene specific probes we have analyzed RNA from different tissues and found these three genes are differentially expressed. A1 mRNA is detected in all tissues analyzed and more abundant in leaves during the light phase of growth. The other two genes are expressed either primarily in flowers A3 or in seeds A2 . In situ hybridization demonstrated that all three genes are expressed in many cells of the seeds and developing seed pods. The A1 and A3 genes are expressed in the sepals and petals of flowers as well as the outer layer of the style but are not expressed in the transmitting tract or on the stigmatal surface. The A2 gene is weakly expressed only in the transmitting tissue of the style. All three genes are also expressed in the guard cells of sepals. These data suggest multiple roles for aspartic proteinases besides those proposed in seeds. Keywords Arabidopsis guard cells in situ hybridization protein glycosylation proteinase. We have been studying the aspartic proteinase genes in Arabidopsis with the goal of understanding their function in the whole plant. Aspartic proteinases EC 3.4.23 are one of the major classes of proteolytic enzymes found in plant and animal viruses microbes and plant and animal cells .