Expression pattern of the 10 mitogen-activated protein kinase kinases (MAPKK) encoded on Arabidopsis thaliana genome

Abstract

ABSTRACT Phosphorylation, carried out by kinases, is a pivotal mechanism for all cell signal transduction pathways. In eukaryotic cells, Mitogen-Activated Protein Kinases (MAPK) form modules with three kinases (MAPKKK, MAPKK, and MAPK) that are sequentially activated, participating in multiple signaling mechanisms. The second kinase forming a typical module is called MAP kinase kinase (MAPKK or MKK), which receives the signal from MAPKKK and transmits it to MAPK. The Arabidopsis thaliana genome has 10 MKKs and they are classified into four different groups (A, B, C, and D). To date, several aspects of the MKK functioning are known, but there is little information about MKK expression in plant tissues. Here, each MKK upstream region was fused to the UidA reporter, and these pMKK1-10:UidA constructions were used to reveal the MKK expression patterns in the tissues of the seedlings during their early development. This experimental expression analysis was complemented with a detailed bioinformatic analysis focused on identifying the cis-regulatory elements present in these upstream promoter regions.