PLANT PHYSIOLOGY , Vol 108, Issue 4 1623-1629, Copyright © 1995 by American Society of Plant Biologists
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GENE REGULATION AND MOLECULAR GENETICS |
Mitochondrial Pyruvate Dehydrogenase (Molecular Cloning of the E1[alpha] Subunit and Expression Analysis)
CPL. Grof, B. M. Winning, T. P. Scaysbrook, S. A. Hill and C. J. Leaver
Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, United Kingdom
A polymerase chain reaction-based approach was used to isolate cDNA clones
encoding the E1[alpha] subunit of the mitochondrial pyruvate dehydrogenase
from higher plants. Putative full-length clones were identified on the
basis of similarity to E1[alpha] sequences from nonplant sources. Southern
blot analysis revealed a small family of genes in potato (Solanum tuberosum
L.), whereas in cucumber (Cucumis sativus) there are only one or two genes.
Tissue-spefific variation in the relative amounts of E1[alpha] mRNA was
observed in northern blot analysis of different potato tissues, with the
highest steady-state transcript levels found in floral tissue. Measurement
of pyruvate dehydrogenase activity in cucumber cotyledons showed that there
is a transient increase to a maximum at 4 to 5 d postimbibition. Western
blot analysis revealed that the amount of E1[alpha] protein also peaks at
this time. Steady-state transcript levels in germinating cucumber
cotyledons also show transient accumulation, peaking 2 d postimbibition.
These data are consistent with regulation of E1[alpha] at the level of
transcription and/or mRNA stability in postgerminative cucumber cotyledons.
