Characterization of P69E and P69F, two differentially regulated genes encoding new members of the subtilisin-like proteinase family from tomato plants

Subtilisin-like proteins represent an ancient family of serine proteases th at are extremely widespread in living organisms. We report here the structu re and genomic organization of two new transcriptionally active genes encod ing proteins that belong to the P69 family of subtilisin-like proteases fro m tomato (Lycopersicon esculentum) plants. The two new members, P69E and P6 9F, are organized in a cluster and arranged in a tandem form. mRNA expressi on analysis and studies of transgenic Arabidopsis plants transformed with p romoter-P-glucuronidase fusions for each of these two genes revealed that t hey are differentially regulated, with each showing a highly specific mRNA expression pattern. P69E mRNA is expressed only in roots, while P69F mRNA i s expressed only in hydathodes. A comparison of all the P69 amino acid sequ ences, gene structure, expression profiles, and clustered organization sugg ests a working model for P69 gene family evolution.