Abstract
In plant and mammalian cells, excess lysine is catabolized by a pathway that is initiated by two enzymes, namely, lysine-ketoglutarate reductase and saccharopine dehydrogenase. In this study, we report the cloning of an Arabidopsis cDNA encoding a bifunctional polypeptide that contains both of these enzyme activities linked to each other. RNA gel blot analysis identified two mRNA bands-a large mRNA containing both lysine-ketoglutarate reductase and saccharopine dehydrogenase sequences and a smaller mRNA containing only the saccharopine dehydrogenase sequence. However, DNA gel blot hybridization using either the lysine-ketoglutarate reductase or the saccharopine dehydrogenase cDNA sequence as a probe suggested that the two mRNA populations apparently are encoded by the same gene. To test whether these two mRNAs are functional, protein extracts from Arabidopsis cells were fractionated by anion exchange chromatography. This fractionation revealed two separate peaks-one containing both coeluted lysine-ketoglutarate reductase and saccharopine dehydrogenase activities and the second containing only saccharopine dehydrogenase activity. RNA gel blot analysis and in situ hybridization showed that the gene encoding lysine-ketoglutarate reductase and saccharopine dehydrogenase is significantly upregulated in floral organs and in embryonic tissues of developing seeds. Our results suggest that lysine catabolism is subject to complex developmental and physiological regulation, which may operate at gene expression as well as post-translational levels.
Full Text
The Full Text of this article is available as a PDF (3.4 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bradford M. M. 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. doi: 10.1016/0003-2697(76)90527-3. [DOI] [PubMed] [Google Scholar]
- Brochetto-Braga M. R., Leite A., Arruda P. Partial purification and characterization of lysine-ketoglutarate reductase in normal and opaque-2 maize endosperms. Plant Physiol. 1992 Mar;98(3):1139–1147. doi: 10.1104/pp.98.3.1139. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dancis J., Hutzler J., Cox R. P., Woody N. C. Familial hyperlysinemia with lysine-ketoglutarate reductase insufficiency. J Clin Invest. 1969 Aug;48(8):1447–1452. doi: 10.1172/JCI106110. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Falco S. C., Guida T., Locke M., Mauvais J., Sanders C., Ward R. T., Webber P. Transgenic canola and soybean seeds with increased lysine. Biotechnology (N Y) 1995 Jun;13(6):577–582. doi: 10.1038/nbt0695-577. [DOI] [PubMed] [Google Scholar]
- Feller A., Dubois E., Ramos F., Piérard A. Repression of the genes for lysine biosynthesis in Saccharomyces cerevisiae is caused by limitation of Lys14-dependent transcriptional activation. Mol Cell Biol. 1994 Oct;14(10):6411–6418. doi: 10.1128/mcb.14.10.6411. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fjellstedt T. A., Robinson J. C. Purification and properties of L-lysine-alpha-ketoglutarate reductase from human placenta. Arch Biochem Biophys. 1975 Jun;168(2):536–548. doi: 10.1016/0003-9861(75)90285-4. [DOI] [PubMed] [Google Scholar]
- Galili G. Regulation of Lysine and Threonine Synthesis. Plant Cell. 1995 Jul;7(7):899–906. doi: 10.1105/tpc.7.7.899. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ghislain M., Frankard V., Vandenbossche D., Matthews B. F., Jacobs M. Molecular analysis of the aspartate kinase-homoserine dehydrogenase gene from Arabidopsis thaliana. Plant Mol Biol. 1994 Mar;24(6):835–851. doi: 10.1007/BF00014439. [DOI] [PubMed] [Google Scholar]
- Goncalves-Butruille M., Szajner P., Torigoi E., Leite A., Arruda P. Purification and Characterization of the Bifunctional Enzyme Lysine-Ketoglutarate Reductase-Saccharopine Dehydrogenase from Maize. Plant Physiol. 1996 Mar;110(3):765–771. doi: 10.1104/pp.110.3.765. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hinnebusch A. G. Mechanisms of gene regulation in the general control of amino acid biosynthesis in Saccharomyces cerevisiae. Microbiol Rev. 1988 Jun;52(2):248–273. doi: 10.1128/mr.52.2.248-273.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Joshi C. P. An inspection of the domain between putative TATA box and translation start site in 79 plant genes. Nucleic Acids Res. 1987 Aug 25;15(16):6643–6653. doi: 10.1093/nar/15.16.6643. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Karchi H., Shaul O., Galili G. Lysine synthesis and catabolism are coordinately regulated during tobacco seed development. Proc Natl Acad Sci U S A. 1994 Mar 29;91(7):2577–2581. doi: 10.1073/pnas.91.7.2577. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kieber J. J., Rothenberg M., Roman G., Feldmann K. A., Ecker J. R. CTR1, a negative regulator of the ethylene response pathway in Arabidopsis, encodes a member of the raf family of protein kinases. Cell. 1993 Feb 12;72(3):427–441. doi: 10.1016/0092-8674(93)90119-b. [DOI] [PubMed] [Google Scholar]
- Markovitz P. J., Chuang D. T., Cox R. P. Familial hyperlysinemias. Purification and characterization of the bifunctional aminoadipic semialdehyde synthase with lysine-ketoglutarate reductase and saccharopine dehydrogenase activities. J Biol Chem. 1984 Oct 10;259(19):11643–11646. [PubMed] [Google Scholar]
- May M. J., Leaver C. J. Oxidative Stimulation of Glutathione Synthesis in Arabidopsis thaliana Suspension Cultures. Plant Physiol. 1993 Oct;103(2):621–627. doi: 10.1104/pp.103.2.621. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Møller B. L. Lysine Catabolism in Barley (Hordeum vulgare L.). Plant Physiol. 1976 May;57(5):687–692. doi: 10.1104/pp.57.5.687. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Noda C., Ichihara A. Purification and properties of L-lysine-alpha-ketoglutarate reductase from rat liver mitochondria. Biochim Biophys Acta. 1978 Aug 7;525(2):307–313. doi: 10.1016/0005-2744(78)90225-5. [DOI] [PubMed] [Google Scholar]
- Ramos F., Dubois E., Piérard A. Control of enzyme synthesis in the lysine biosynthetic pathway of Saccharomyces cerevisiae. Evidence for a regulatory role of gene LYS14. Eur J Biochem. 1988 Jan 15;171(1-2):171–176. doi: 10.1111/j.1432-1033.1988.tb13773.x. [DOI] [PubMed] [Google Scholar]