PLANT PHYSIOLOGY , Vol 109, Issue 2 611-618, Copyright © 1995 by American Society of Plant Biologists
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WHOLE PLANT, ENVIRONMENTAL, AND STRESS PHYSIOLOGY |
A Rapeseed Cold-Inducible Transcript Encodes a Phosphoenolpyruvate Carboxykinase
J. Saez-Vasquez, M. Raynal and M. Delseny
Laboratoire de Physiologie et Biologie Moleculaire des Plantes, Unite de Recherche Associee 565 du Centre National de la Recherche Scientifique, Universite de Perpignan, Avenue de Villeneuve, 66860, Perpignan-Cedex, France
We have isolated a clone corresponding to a new cold-regulated gene from a
cDNA library made from rapeseed (Brassica napus cv Samourai)
cold-acclimated etiolated seedlings. Sequence analysis and homology
searches showed that this clone encodes a protein highly homologous to the
ATP-dependent phosphoenolpyruvate carboxykinase (PEPCK; EC 4.1.1.49) from
Saccharomyces cerevisiae, Trypanosoma, Rhizobium sp., and Escherichia coli;
we refer to the B. napus clone as BnPEPCK. A potential ATP-binding site
existing in all PEPCK proteins was also found in BnPEPCK. Although there
was a basal expression of BnPEPCK in seedlings grown at control, room
temperature, the steady-state level of the transcripts increased at 4[deg]C
and decreased to normal levels when the seedlings were returned to control
temperature (22[deg]C). Using antibodies made against a recombinant
histidine-BnPEPCK fusion protein, we demonstrated that BnPEPCK protein
level is correlated with the accumulation of the BnPEPCK transcript.
