PLANT PHYSIOLOGY , Vol 108, Issue 1 141-148, Copyright © 1995 by American Society of Plant Biologists
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DEVELOPMENT AND GROWTH REGULATION |
Three Glycosylated Polypeptides Secreted by Several Embryogenic Cell Cultures of Pine Show Highly Specific Serological Affinity to Antibodies Directed against the Wheat Germin Apoprotein Monomer
J. M. Domon, B. Dumas, E. Laine, Y. Meyer, A. David and H. David
Laboratoire de Biotechnologie et Physiologie Vegetales, EA 908, Universite de Picardie Jules Verne, 33, Rue Saint-Leu, 80039 Amiens, France (J.-M.D., E.L., A.D., H.D.)
Embryogenic tissues of Pinus caribaea Morelet var hondurensis produce
extracellular proteins; among them germins have been identified.
Two-dimensional electrophoresis followed by electroblotting onto a
polyvinylidene difluoride membrane allowed isolation and N-terminal amino
acid sequencing of extracellular GP111, which is present within the five
embryogenic cell lines studied. The amino acid sequence showed strong
homologies with the sequences of germins deduced from cDNA sequencing,
starting at the same amino acid position but one, compared with other
sequences of mature germins deduced from protein sequencing. Immunoblots of
embryogenic and nonembryogenic extracellular proteins indicated that the
polypeptide GP111 plus two others with similar relative molecular mass
values are present in embryogenic cell lines but not in nonembryogenic
ones. They were recognized by an antiserum raised against the
nonglycosylated monomer of wheat germin. The cross-reaction between pine
and wheat apoproteins was highly specific. An antiserum against the
glycosylated pentameric germin-like protein (an oxalate oxidase) of barley
cross-reacted with all three, as well as with several other glycosylated
polypeptides.
