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Regulation of tomato HMG1 during cell proliferation and growth (1999)

Jelesko, John G. ; Jenkins, Susan M. ; Rodríguez-Concepción, Manuel ; [et al.]

Springer

Planta 208 (1999), S. 310-318

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ISSN: 1432-2048

Keywords: Keywords:β-Glucuronidase ; 3-Hydroxy-3-methylglu- taryl coenzyme A reductase ; Lycopersicon (HMG1 regulation) ; Mevalonic acid ; Transgenic tomato ; Transient gene expression (HMG1)

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract. The enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR, EC 1.1.1.34) is encoded by a small multigene family in tomato (Lycopersiconesculentum Mill.) and catalyzes the synthesis of mevalonic acid (MVA), a committed step in the biosynthesis of sterols and isoprenoids. A chimeric HMG1::GUS reporter gene fusion was used to analyze the regulation of HMG1 gene expression in detail. HMG1 promoter 5′ deletion mutants established the boundary of a fully inducible promoter. In HMG1::GUS transgenic tomato plants, histochemical staining with 5-bromo-3-indolyl-glucuronide demonstrated that HMG1 was primarily expressed in shoot and root meristems, and in young tomato fruit. This result was confirmed by both HMG1 in-situ hybridization and RNA gel blot analysis. Tomato suspension cell experiments showed that steady-state HMG1 mRNA accumulated during lag and exponential growth phases, but not during the stationary phase. Transient expression of the HMG1::GUS in tissue culture cells treated with mevinolin indicated that HMG1 expression was subject to feedback regulation by a biosynthetic product derived from MVA. These results suggest that a primary, although not exclusive, role of HMG1 is to supply the MVA demand associated with cell division and growth.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s004250050564

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C—H and N—H bond activation in reactions of vinyl acetate, allyl cyanide, allylamine and other amines with (η-C5H5)2Rh2(CO)(CF3C2CF3) (1990)

Dickson, Ron S ; Jenkins, Susan M

New York, NY [u.a.] : Wiley-Blackwell

Applied Organometallic Chemistry 4 (1990), S. 493-501

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ISSN: 0268-2605

Keywords: C—H activation ; N—H activation ; (η-C5H5)2Rh2(CO)(CF3C2CF3) ; alkenyl ; carboxamide ; Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: There is activation of olefinic C—H bonds when (η-C5H5)2Rh2(CO)(CF3C2CF3) is treated with vinyl acetate or allyl cyanide. These reactions are initiated by exposure to sunlight. In the vinyl acetate reaction, each of the three vinylic C—H bonds can be broken, but there is strong preference for cleavage at the substituted carbon. The products formed in these reactions are bisalkenyl complexes of the type (η-C5H5)2Rh2{μ-C(CF3)C(CF3)H}(μ-CR=CR′R″), and all isomers have been thoroughly characterized by NMR analysis. Similar reactions with allylamine and other amines (NH2R, NHMe2) occur in the dark and proceed by N—H bond cleavage. Near-quantitative amounts of the products, (η-C5H5)Rh2{C(CF3)C(CF3)H}(C(O)NRR′) are isolated. Spectroscopic data indicate a bridging carboxamide ligand attached to the Rh—Rh bond from oxygen and nitrogen donor sites. It is proposed that coordination of O or N to rhodium has a strong influence on all of the reactions studied.

Additional Material: 3 Tab.