CHARACTERIZATION OF GENES FOR 2-COMPONENT PHOSPHORELAY MEDIATORS WITHA SINGLE HPT DOMAIN IN ARABIDOPSIS-THALIANA

Three cDNAs that encode two-component phosphorelay-mediator-like prote ins were cloned from Arabidopsis thaliana, Putative proteins (ATHP1-3) contain an HPt (Histidine-containing Phospho transfer)-like domain wi th a conserved histidine and some invariant residues that are involved in phosphorelay. Growth retardation of YPD1-disrupted yeast cells was reversed with ATHPs, which indicates that ATHPs function as phosphore lay mediators in yeast cells, The ATHP genes are expressed more in roo ts than in other tissues, similar to the expression of genes for a sen sor histidine kinase, ATHK1, and response regulators ATRR1-4. These re sults suggest that ATHPs function as two-component phosphorelay mediat ors between sensor histidine kinase and response regulators in Arabido psis. (C) 1998 Federation of European Biochemical Societies.