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Molecular cloning of cucumber phosphoenolpyruvate carboxykinase and developmental regulation of gene expression
Citation
Kim, D-J and Smith, SM, Molecular cloning of cucumber phosphoenolpyruvate carboxykinase and developmental regulation of gene expression, Plant Molecular Biology, 26, (1) pp. 423-434. ISSN 0167-4412 (1994) [Refereed Article]
Copyright Statement
Copyright 1994 Kluwer Academic Publishers
Official URL: http://link.springer.com/article/10.1007%2FBF00039...
Abstract
A cDNA library from RNA of senescing cucumber cotyledons was screened for sequences also expressed
in cotyledons during post-germinative growth. One clone encodes ATP-dependent phosphoenolpyruvate
carboxykinase (PCK; EC 4.1.1.49), an enzyme of the gluconeogenic pathway. The sequence of a fulllength
cDNA predicts a polypeptide of 74 397 Da which is 43 Yo, 49~o and 57~o identical to bacterial,
trypanosome and yeast enzymes, respectively. The cDNA was expressed in Escherichia coli and antibodies
raised against the resultant protein. The antibody recognises a single polypeptide of ca. 74 kDa,
in extracts of cotyledons, leaves and roots. The cucumber genome contains a single pck gene. In the
seven-day period after seed imbibition, PCK mRNA and protein steady-state levels increase in amount
in cotyledons, peaking at days 2 and 3 respectively, and then decrease. Both accumulate again to a low
level in senescing cotyledons. This pattern of gene expression is similar to that of isocitrate lyase (ICL)
and malate synthase (MS). When green cotyledons are detached from seedlings and incubated in the
dark, ICL and MS mRNAs increase rapidly in amount but PCK mRNA does not. Therefore it seems
unlikely that the glyoxylate cycle serves primarily a gluconeogenic role in starved (detached) cotyledons,
in contrast to post-germinative and senescing cotyledons where PCK, ICL and MS are coordinately
synthesised. While exogenous sucrose greatly represses expression of icl and ms genes in dark-incubated
cotyledons, it has a smaller effect on the level of PCK mRNA.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | cucumber, Cucumis sativus, germination, gluconeogenesis, phosphoenolpyruvate carboxykinase, senescence |
| Research Division: | Biological Sciences |
| Research Group: | Plant Biology |
| Research Field: | Plant Physiology |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding Knowledge |
| Objective Field: | Expanding Knowledge in the Biological Sciences |
| Author: | Smith, SM (Professor Steven Smith) |
| ID Code: | 101589 |
| Year Published: | 1994 |
| Web of Science® Times Cited: | 57 |
| Deposited By: | Plant Science |
| Deposited On: | 2015-06-26 |
| Last Modified: | 2015-09-21 |
| Downloads: | 0 |
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