Studies on the expression of the wheat prolyl isomerase FKBP73 during plant development

Prolyl isomerases are ubiquitous proteins which accelerate the slow steps o f protein folding by isomerisation of peptide bonds in which proline partic ipates. We have isolated and characterised a wheat prolyl isomerase belongi ng to the FK506 binding protein family (FKBP) named wFKBP73. By using polyc lonal antibodies raised against the recombinant wheat FKBP, its expression in wheat organs, during seed imbibition and caryopsis maturation was studie d. The highest level of the wFKBP73 expression was found in imbibed embryos and 2 day old seedlings, whereas the protein could not be detected in matu re green leaves. When young leaves and roots were dissected into segments, the highest expression was associated with the meristematic region. The wFK BP73 accumulated during seed maturation and was present in dry seeds. Its p resence in dry seeds may suggest its importance in assisting correct foldin g of newly synthesized proteins and maintaining the native structure of cer tain macromolecules. The wFKBP73 was determined to be a stable protein with a half life of 41 h. The polyclonal antibodies raised against the recombin ant protein detected cross reacting proteins in barley, corn, rice, and pea suggesting that the FKBP73 is a conserved protein in plants. The wFKBP loc us Xtavl926(Fkbp) was mapped on the short arm of the wheat group seven chro mosome. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.