Nitrate reductase gene expression

Back, E., Dunne, W., Schneiderbauer, A., de Framond, A., Rastogi, R. Rothstein, S.J. (1991). Isolation of the spinach nitrite reductase gene promoter which confers nitrate inducibility on GUS gene expression in transgenic tobacco. Plant Molecular Biology 17, 9-18. 

Cheng, C.-L., Acedo, G.N., Dewdney, J., Goodman, H.M. Con-kling, M.A. (1991). Differential expression of the two Arabidopsis nitrate reductase genes. Plant Physiology 96, 275-9. 

Galangau, F., Daniel-Vedele, F., Moureaux, T., Dorbe, M.-F., Leydecker, M.-T. Caboche, M. (1988). Expression of leaf nitrate reductase genes from tomato and tobacco in relation to light-dark regimes and nitrate supply. Plant Physiology 88, 383-8. 

Gowri, G. Campbell, W.H. (1989). cDNA clones for corn leaf NAD-H nitrate reductase and chloroplast NAD(P)+ glyceraldehyde-3-phosphate dehydrogenase. Characterization of the clones and analysis of the expression of the genes in leaves as influenced by nitrate in the light and dark. Plant Physiology 90, 792-8. 

Hoff, T., Stummann, B.M. Henningsen, K.W. (1991). Cloning and expression of a gene encoding a root-specific nitrate reductase in bean (Phaseolus vulgaris). Physiologia Plantarum 82, 197-204. 

Seith, B., Schuster, C. Mohr, H. (1991). Coaction of light, nitrate and a plastidic factor in controlling nitrate-reductase gene expression in spinach. Planta 184, 74-80. 

Attempts to understand the molecular basis for the induction of synthesis of specific proteins/enzymes are discussed in most of the chapters, but some topics are more advanced in this respect than others. In most cases induction is due to activation of gene expression, as measured by increased steady state levels of mRNA, but in some cases, for instance nitrate reductase, post-transcriptional events may also be important. The eventual aim of course is to understand the series of events - the so-called signal transduction pathway - which lead from perception of the signal to increased mRNA levels and hence increased enzyme synthesis. In a... 

Song, B., and Ward, B. B. (2004). Molecular characterization ofthe assimilatory nitrate reductase gene and its expression in the marine green alga Dunaliella tertiolecta (Chlorophyceae). J. Phycol. 40, 721-731. 

The enzyme activity is induced by both NOj" and Mo when in the presence of each other. The induction of enzyme activity by N03" is a slow process and requires mRNA-dependent synthesis of apoprotein, whereas the induction of enzyme activity by Mo is much faster, as it involves only rapid activation of the apoprotein by Mo (Jones et al., 1976, 1978). Notion and Hewitt (1979) showed that the Mo-free apoenzyme could be activated by addition of Mo complex obtained from acid washings of the native enzyme. Tungsten (W) can substitute for Mo in nitrate reductase, but the enzyme activity is decreased (Heimer, Wray, and Filner, 1969), as the formation of an active Mo cofactor is prevented. In an experiment with W-treated tobacco (Nicotiana tabacum) plants supplied with N as NOs , Deng, Moureaux, and Caboche (1989) reported a decrease in nitrate reductase activity, but several-fold increases in the accumulation of nitrate reductase apoprotein and corresponding mRNA because of excessive expression of a nitrate reductase structural gene. 

That deregulation in nitrate reductase gene expression could possibly have been due to a modified transcription rate for the nitrate reductase gene or a modified translation rate for nitrate reductase mRNA, or it could have been due to interference with nitrate reduction, which could have limited reduced N metabolites to low levels. Further studies are needed to examine these possibilities. 

Deng, M., Moureaux, T., and Caboche, M. (1989). Tungstate and molybdenum analog inactivating nitrate reductase, deregulates the expression of the nitrate reductase structural gene. Plant Physiol. 91 304-9. 

Sodergren E J, Hsu P Y, DeMoss J A (1998). Roles of the narJ and narl gene products in the expression of nitrate reductase in Escherichia coli. J. Biol. Chem. 263 16156-16162. 

Moreno, R., Zafra, O., Cava, F., and Berenguer, J. (2003) Development of a gene expression vector for Jhermus thermophilus based on the promoter of the respiratory nitrate reductase. 

Figure 18-12 A stable form of nitrate reductase for NO3 analysis is made on a commercial scale from yeast in a 14-L fermentor. Recombinant DNA technology permits nitrate reductase genes from the flowering plant called thale cress to be expressed by yeast.

Nitrate assimilation is an important process in rice regeneration. A quantitative trait loci gene encoding the ferrodoxin-nitiite reductase (NiR), an enzyme that catalyzes the reduction of nitrite to ammonium leading to the accumulation of toxic nitrite in culture media, was isolated from the high-regeneration rice strain Kasalath. The level of NiR expression in the... 

Kramer etfl/., 1989 Wvalle eta/., 1989). Nitrite reductase mRNA was present in small amounts in uninduced leaves of both species but not in roots of maize. Induction by nitrate increased the NiR mRNA in both species and in both the roots and leaves of maize. Perhaps one of the two NiR genes present in maize is expressed constitutively in leaves (Kramer et al., 1989). The NiR mRNA induction pattern in maize (Kramer et al., 1989) is similar to the NR mRNA induction pattern in barley (Melzer et al., 1989). Nitrite reductase mRNA is rapidly induced by nitrate, reaching a peak within 5 hr and then declining to a lower level even in the presence of continued nitrate. The NiR mRNA appears to be short lived with a half-life as short as 30 min (Kramer et al, 1989). The mechanisms regulating these fluctuations in NiR mRNA are not known at this time. Nitrite was capable of limited induction of NiR mRNA in spinach leaves (Back etal, 1988), although the role of nitrite is equivocal due to Ae possibility of in vivo oxidation of nitrite to nitrate (Aslam et al, 1987). 

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