Plant Physiol. Drug Metab Dispos
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on June 20, 2002; 10.1104/pp.001438

This Article
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow All Versions of this Article:
129/3/1095    most recent
pp.001438v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Web of Science (19)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Devarenne, T. P.
Right arrow Articles by Chappell, J.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Devarenne, T. P.
Right arrow Articles by Chappell, J.
Agricola
Right arrow Articles by Devarenne, T. P.
Right arrow Articles by Chappell, J.

Received December 4, 2001
Accepted March 18, 2002

Regulation of Squalene Synthase, a Key Enzyme of Sterol Biosynthesis, in Tobacco

Timothy P. Devarenne , Anirban Ghosh , and Joe Chappell *

Plant Physiology/Biochemistry/Molecular Biology Program, Agronomy Department (T.P.D., J.C.), and Center on Aging, College of Medicine (A.G.), University of Kentucky, Lexington, Kentucky 40546

* Corresponding author; email: chappell{at}uky.edu.

Squalene synthase (SS) represents a putative branch point in the isoprenoid biosynthetic pathway capable of diverting carbon flow specifically to the biosynthesis of sterols and, hence, is considered a potential regulatory point for sterol metabolism. For example, when plant cells grown in suspension culture are challenged with fungal elicitors, suppression of sterol biosynthesis has been correlated with a reduction in SS enzyme activity. The current study sought to correlate changes in SS enzyme activity with changes in the level of the corresponding protein and mRNA. Using an SS-specific antibody, the initial suppression of SS enzyme activity in elicitor-challenged cells was not reflected by changes in the absolute level of the corresponding polypeptide, implicating a post-translational control mechanism for this enzyme activity. In comparison, the absolute level of the SS mRNA did decrease approximately 5-fold in the elicitor-treated cells, which is suggestive of decreased transcription of the SS gene. Study of SS in intact plants was also initiated by measuring the level of SS enzyme activity, the level of the corresponding protein, and the expression of SS gene promoter-reporter gene constructs in transgenic plants. SS enzyme activity, polypeptide level, and gene expression were all localized predominately to the shoot apical meristem, with much lower levels observed in leaves and roots. These later results suggest that sterol biosynthesis is localized to the apical meristems and that apical meristems may be a source of sterols for other plant tissues.




This article has been cited by other articles:


Home page
 Plant Cell PhysiolHome page
M.-H. Lee, J.-H. Jeong, J.-W. Seo, C.-G. Shin, Y.-S. Kim, J.-G. In, D.-C. Yang, J.-S. Yi, and Y.-E. Choi
Enhanced Triterpene and Phytosterol Biosynthesis in Panax ginseng Overexpressing Squalene Synthase Gene
Plant Cell Physiol., August 15, 2004; 45(8): 976 - 984.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY® THE PLANT CELL
Copyright © 2002 by the American Society of Plant Biologists