The wheat peptidyl prolyl cis-trans-isomerase FKBP77 is heat induced and developmentally regulated

We isolated a cDNA encoding a 568-amino acid, heat-stress-induced peptidyl prolyl isomerase belonging to the FK506-binding-protein (FKBP) family. The open reading frame encodes for a peptidyl prolyl isomerase that possesses t hree FKBP-12-like domains, a putative tetratricopeptide motif, and a calmod ulin-binding domain. Specific antibodies showed that the open reading frame encodes a heat-induced 77-kD protein, the wheat FKBP77 (wFKBP77), which ex hibits 84% identity with the wFKBP73 and 42% identity with the human FKBP59 . Because of the high similarity in sequence to wFKBP73, wFKBP77 was design ated as the heat-induced isoform. The wFKBP77 mRNA steady-state level was 1 4-fold higher at 37 degrees C than at 25 degrees C. The wFKBP77 transcript abundance was the highest in mature embryos that had imbibed and 2-d-old gr een shoots exposed to 37 degrees C, and decreased to 6% in 6-d-old green sh oots. The transcript level returned to the level detected at 25 degrees C a fter recovery of the embryos for 90 min at 25 degrees C. We compared wFKBP7 3 and wFKBP77 with the heat-shock proteins having cognate and heat-stress-i nduced counterparts.