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Sucrose regulation of ADP-glucose pyrophosphorylase subunit genes transcript levels in leaves and fruitsADP-glucose pyrophosphorylase (AGPase, EC2.7.7.27) is a key regulatory enzyme in starch biosynthesis. The enzyme is a heterotetramer with two S and two B subunits. In tomato, there are three multiple forms of the S subunit gene. Agp S1, S2 and B are highly expressed in fruit from 10 to 25 days after anthesis. Agp S3 is only weakly expressed in fruit. Sucrose significantly elevates expression of Agp S1, S2 and B in both leaves and fruits. Agp S1 exhibits the highest degree of regulation by sucrose. In fact, sucrose may be required for Agp S1 expression. For excised leaves incubated in water, no transcripts for Agp S1 could be detected in the absence of sucrose, whereas it took up to 16 h in water before transcripts were no longer detectable for Agp S2 and B. Neither Agp S3 nor the tubulin gene is affected by sucrose, demonstrating that this response is specifically regulated by a carbohydrate metabolic signal, and is not due to a general increase in metabolism caused by sucrose treatment. Truncated versions of the promoter for Agp S1 indicate that a specific region 1.3-3.0 kb upstream from the transcription site is responsible for sucrose sensitivity. This region of the S1 promoter contains several cis-acting elements present in the promoters of other genes that are also regulated by sucrose. c2002 Elsevier Science Ireland Ltd. All rights reserved.
Document ID
20040088346
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Li, Xiangyang
(Rutgers University New Brunswick, NJ 08901-8520, United States)
Xing, Jinpeng
Gianfagna, Thomas J.
Janes, Harry W.
Date Acquired
August 21, 2013
Publication Date
February 1, 2002
Publication Information
Publication: Plant science (Shannon, Ireland)
Volume: 162
Issue: 2
ISSN: 0168-9452
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAG5-6011
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Life Support Systems

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