• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of plntcellLink to Publisher's site
Plant Cell. Oct 1994; 6(10): 1401–1414.
PMCID: PMC160529

Distinct phenotypes generated by overexpression and suppression of S-adenosyl-L-methionine synthetase reveal developmental patterns of gene silencing in tobacco.


S-Adenosyl-L-methionine synthetase (SAM-S) catalyzes the conversion of L-methionine and ATP into S-adenosyl-L-methionine. Tobacco plants that were transformed with a construct allowing high transcription levels of an Arabidopsis sam-s gene could be grouped into two main classes based on their morphology. One class developed yellow-green leaves and had high SAM-S activity and transgene mRNA levels, whereas the other class was stunted and had leather-like leaves, very low SAM-S activity, and suppressed mRNA level of the transgene. Because both overexpression and silencing of transgene expression led to distinct, abnormal phenotypes, the developmental pattern of transgene silencing was visualized. In the lower leaves, the suppressed phenotype was associated with the veins. In successive leaves, the area of the suppressed tissue increased until all newly developed leaves displayed the suppressed phenotype. In this study, a hypothesis is presented for this developmental gene silencing. Furthermore, transgenic plants with suppressed SAM-S activity had a characteristic smell, a consequence of the accumulation of L-methionine that is converted into the volatile methanethiol.

Full Text

The Full Text of this article is available as a PDF (3.3M).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Bradford MM. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. [PubMed]
  • Cherest H, Surdin-Kerjan Y, Antoniewski J, de Robichon-Szulmajster H. Effects of regulatory mutations upon methionine biosynthesis in Saccharomyces cerevisiae: loci eth2-eth3-eth10. J Bacteriol. 1973 Sep;115(3):1084–1093. [PMC free article] [PubMed]
  • Deblaere R, Bytebier B, De Greve H, Deboeck F, Schell J, Van Montagu M, Leemans J. Efficient octopine Ti plasmid-derived vectors for Agrobacterium-mediated gene transfer to plants. Nucleic Acids Res. 1985 Jul 11;13(13):4777–4788. [PMC free article] [PubMed]
  • de Carvalho F, Gheysen G, Kushnir S, Van Montagu M, Inzé D, Castresana C. Suppression of beta-1,3-glucanase transgene expression in homozygous plants. EMBO J. 1992 Jul;11(7):2595–2602. [PMC free article] [PubMed]
  • Giovanelli J, Veluthambi K, Thompson GA, Mudd SH, Datko AH. Threonine Synthase of Lemna paucicostata Hegelm. 6746. Plant Physiol. 1984 Oct;76(2):285–292. [PMC free article] [PubMed]
  • Giovanelli J, Mudd SH, Datko AH. Regulatory Structure of the Biosynthetic Pathway for the Aspartate Family of Amino Acids in Lemna paucicostata Hegelm. 6746, with Special Reference to the Role of Aspartokinase. Plant Physiol. 1989 Aug;90(4):1584–1599. [PMC free article] [PubMed]
  • Greene RC, Su CH, Holloway CT. S-Adenosylmethionine synthetase deficient mutants of Escherichia coli K-12 with impaired control of methionine biosynthesis. Biochem Biophys Res Commun. 1970 Mar 27;38(6):1120–1126. [PubMed]
  • Greene RC, Hunter JS, Coch EH. Properties of metK mutants of Escherichia coli K-12. J Bacteriol. 1973 Jul;115(1):57–67. [PMC free article] [PubMed]
  • A simple and general method for transferring genes into plants. Science. 1985 Mar 8;227(4691):1229–1231. [PubMed]
  • Logemann J, Schell J, Willmitzer L. Improved method for the isolation of RNA from plant tissues. Anal Biochem. 1987 May 15;163(1):16–20. [PubMed]
  • Madison JT, Thompson JF. Threonine synthetase from higher plants: stimulation by S-adenosylmethionine and inhibition by cysteine. Biochem Biophys Res Commun. 1976 Jul 26;71(2):684–691. [PubMed]
  • Markham GD, DeParasis J, Gatmaitan J. The sequence of metK, the structural gene for S-adenosylmethionine synthetase in Escherichia coli. J Biol Chem. 1984 Dec 10;259(23):14505–14507. [PubMed]
  • Martienssen R, Baron A. Coordinate suppression of mutations caused by Robertson's mutator transposons in maize. Genetics. 1994 Mar;136(3):1157–1170. [PMC free article] [PubMed]
  • Martienssen R, Barkan A, Taylor WC, Freeling M. Somatically heritable switches in the DNA modification of Mu transposable elements monitored with a suppressible mutant in maize. Genes Dev. 1990 Mar;4(3):331–343. [PubMed]
  • Mathur M, Saluja D, Sachar RC. Post-transcriptional regulation of S-adenosylmethionine synthetase from its stored mRNA in germinated wheat embryos. Biochim Biophys Acta. 1991 Jun 24;1078(2):161–170. [PubMed]
  • Mudd SH, Finkelstein JD, Irreverre F, Laster L. Transsulfuration in mammals. Microassays and tissue distributions of three enzymes of the pathway. J Biol Chem. 1965 Nov;240(11):4382–4392. [PubMed]
  • Peleman J, Boerjan W, Engler G, Seurinck J, Botterman J, Alliotte T, Van Montagu M, Inzé D. Strong cellular preference in the expression of a housekeeping gene of Arabidopsis thaliana encoding S-adenosylmethionine synthetase. Plant Cell. 1989 Jan;1(1):81–93. [PMC free article] [PubMed]
  • Peleman J, Saito K, Cottyn B, Engler G, Seurinck J, Van Montagu M, Inzé D. Structure and expression analyses of the S-adenosylmethionine synthetase gene family in Arabidopsis thaliana. Gene. 1989 Dec 14;84(2):359–369. [PubMed]
  • Rafferty JB, Somers WS, Saint-Girons I, Phillips SE. Three-dimensional crystal structures of Escherichia coli met repressor with and without corepressor. Nature. 1989 Oct 26;341(6244):705–710. [PubMed]
  • Rognes SE, Lea PJ, Miflin BJ. S-adenosylmethionine--a novel regulator of aspartate kinase. Nature. 1980 Sep 25;287(5780):357–359. [PubMed]
  • Saint-Girons I, Belfaiza J, Guillou Y, Perrin D, Guiso N, Bârzu O, Cohen GN. Interactions of the Escherichia coli methionine repressor with the metF operator and with its corepressor, S-adenosylmethionine. J Biol Chem. 1986 Aug 15;261(23):10936–10940. [PubMed]
  • Seymour GB, Fray RG, Hill P, Tucker GA. Down-regulation of two non-homologous endogenous tomato genes with a single chimaeric sense gene construct. Plant Mol Biol. 1993 Oct;23(1):1–9. [PubMed]
  • Smith CJ, Watson CF, Bird CR, Ray J, Schuch W, Grierson D. Expression of a truncated tomato polygalacturonase gene inhibits expression of the endogenous gene in transgenic plants. Mol Gen Genet. 1990 Dec;224(3):477–481. [PubMed]
  • Tabor CW, Tabor H. Polyamines. Annu Rev Biochem. 1984;53:749–790. [PubMed]
  • Thomas D, Rothstein R, Rosenberg N, Surdin-Kerjan Y. SAM2 encodes the second methionine S-adenosyl transferase in Saccharomyces cerevisiae: physiology and regulation of both enzymes. Mol Cell Biol. 1988 Dec;8(12):5132–5139. [PMC free article] [PubMed]
  • van der Krol AR, Mur LA, Beld M, Mol JN, Stuitje AR. Flavonoid genes in petunia: addition of a limited number of gene copies may lead to a suppression of gene expression. Plant Cell. 1990 Apr;2(4):291–299. [PMC free article] [PubMed]
  • Van Haute E, Joos H, Maes M, Warren G, Van Montagu M, Schell J. Intergeneric transfer and exchange recombination of restriction fragments cloned in pBR322: a novel strategy for the reversed genetics of the Ti plasmids of Agrobacterium tumefaciens. EMBO J. 1983;2(3):411–417. [PMC free article] [PubMed]

Articles from The Plant Cell are provided here courtesy of American Society of Plant Biologists


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...