About the role of CK2 in plant signal transduction.

Despite increasing progress in the study of CK2 activity in plants, a clear understanding of its functional role remains elusive. The high pleiotropic nature of the enzyme, the fact that it is absolutely necessary to maintain life, and the existence of multiple isoforms have made it difficult to obtain loss-of-function mutants with which to study the impact of CK2 depletion in the organisms. To avoid all these difficulties, we have used a dominant-negative mutant approach, by constructing a CK2α kinase-inactive subunit (CKA3mut) that was cloned downstream of an inducible promoter. Stably transformed Arabidopsis plants showed that longtime inductions of the transgene were lethal, causing growth and development arrests and ultimately resulting in plant death. However, short-time inductions were not lethal and revealed broad phenotypical changes that uncovered novel functions of CK2 in plants. The high pleiotropy of CK2 was sustained by analysis of global transcript profiles that showed a huge number of genes affected, involved in a wide variety of cellular processes.