Nitrate reductase regulation: Effects of nitrate and light on nitrate reductase mRNA accumulation

Melzer, J. M.; Kleinhofs, A.; Warner, Robert L.

doi:10.1007/bf02464902

Cited by 116 publications

(99 citation statements)

References 34 publications

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“…The decline in NR mRNA after peak accumulation in leaves and roots argues for a negative feedback control of NR mRNA synthesis and/or degradation in birch. Probably this reflects a general mechanism of NR regulation in plants, because similar changes of NR mRNA pools following the induction by nitrate were also found in herbaceous species (11,18). Although feedback regulation of NR by products of nitrate assimilation has been reported for fungi (21), the stimuli involved in plants are not known.…”

Section: Induction Of Nirmentioning

confidence: 68%

“…Upon transfer of ammonium-grown seedlings to a nitrate-containing medium, NR activities dramatically increased in leaves and roots of illuminated plants. This induction strictly depends on the presence of light, thus resembling the situation found for NADH-specific NR in herbaceous species (11,18,23 (11). This could not be tested in birch due to the lack of NR-specific antibodies.…”

Section: Induction Of Nirmentioning

confidence: 68%

“…In contrast with barley (18), NR in birch is induced significantly faster in leaves than in roots. This is probably due to an inhibitory effect of ammonium on NR induction detectable only in roots (Table I) Accumulations of NiR-encoding mRNAs following the addition of nitrate have been observed in spinach (1,24), maize (16), and pea (12).…”

Section: Induction Of Nirmentioning

confidence: 69%

See 2 more Smart Citations

Induction of Nitrate Assimilatory Enzymes in the Tree Betula pendula

Friemann

Lange²,

Hachtel³

et al. 1992

Plant Physiol.

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Section: Induction Of Nirmentioning

confidence: 68%

Section: Induction Of Nirmentioning

confidence: 68%

Section: Induction Of Nirmentioning

confidence: 69%

See 1 more Smart Citation

Induction of Nitrate Assimilatory Enzymes in the Tree Betula pendula

Friemann

Lange²,

Hachtel³

et al. 1992

Plant Physiol.

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show abstract

“…In addition to the two determining factors nitrate and carbohydrates, other factors also regulate NR gene expression. Light signals at red/far-red (Rajasekhar et al, 1988;Melzer et al, 1989) and at blue (Melzer et al, 1989) regions of the spectrum both increase the NR mRNA levels of etiolated seedlings. Cytokinin enhances, whereas ABA suppresses, the light induction of NR transcription in etiolated barley leaves (Lu et al, 1990(Lu et al, , 1992.…”

Section: Rp07035-25 and Gm46116 Jb Was Supported By Nih Geneticsmentioning

confidence: 97%

“…To obtain an adequate amount of nitrogen when available, it may be advantageous for the plants to elevate the othenvise low capacity for nitrate reduction to a much higher level. In fact, the response of higher plant NR genes to environmental nitrate is rapid; steady-state mRNA levels increase within 15 to 30 min of nitrate induction (Gowri and Campbell, 1989;Melzer et al, 1989;Cheng et al, 1991). In addition to the two determining factors nitrate and carbohydrates, other factors also regulate NR gene expression.…”

Section: Rp07035-25 and Gm46116 Jb Was Supported By Nih Geneticsmentioning

confidence: 99%

5[prime] Proximal Regions of Arabidopsis Nitrate Reductase Genes Direct Nitrate-Induced Transcription in Transgenic Tobacco

et al. 1994

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Nitrate redudase (NR) is the first enzyme in nitrate assimilation, a critica1 process for plant survival. l h e regulation of NR gene expression is complex, involving both interna1 and externa1 factors. O f these, nitrate indudion of NR gene expression has been studied most extensively and is well conserved among baderia, fungi, and higher plants. We are interested in understanding the mechanism of nitrate indudion of higher plant NR genes. Here we describe promoter analyses of the 5' flanking regions of the Arabidopsis NR genes, NR1 and NRZ, with resped to nitrate indudion of gene expression. To facilitate these analyses, a nitrate indudion procedure using 1, transgenic tobacco plants was established. Approximately 1.5-kb 5' flanking regions of the two Arabidopsis NR genes (NR1 and NRZ) were fused to a reporter gene and its expression in transgenic plants was analyzed. Deletion analyses of these regions show that 238-and 188-bp 5' flanking regions of the NR1 and NRZ, respedively, contain sequences responsive to nitrate indudion.

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Nitrate reductase: A model system for the investigation of enzyme induction in eukaryotes

Pike

Cohen

Monroe

2002

Biochem Molecular Bio Educ

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Plant nitrate reductase is an easily studied enzyme whose induction by various signals can be explored in inquiry-based undergraduate laboratories. Barley, mustard, and radish seedlings are grown for 3-7 days with different light conditions and nitrogen nutrition. The enzyme activity of crude extracts is assayed in a colorimetric procedure. The protocols can be used in student independent research projects.Keywords: Nitrate reductase, enzyme induction, enzyme assay, independent projects.As part of courses in many areas of biochemistry and molecular biology, students explore the environmental, developmental, biochemical, and physiological controls on enzyme activity, at the level both of gene expression and of enzyme activation and inhibition (post-translational control). Although there are many useful laboratory examples of such controls in prokaryotes, nitrate reductase in plants is a very suitable eukaryotic model for these concepts. Laboratory studies with this system can range from a straightforward presentation of fundamental concepts to extended student-designed independent projects; indeed, the enzyme could be the focus of a wide-ranging laboratory program. A further advantage is that both in vitro and in vivo enzyme assay protocols are available, so students can compare results from the two. Although published reports discussed below indicate unambiguously that many of the changes in enzyme activity we describe are the result of changes in gene expression, it should be apparent that, aside from experiments with inhibitors of transcription and translation, the protocols we describe do not explicitly demonstrate that point.Ross [1] first published a laboratory exercise on this system over 25 years ago. In the work in our courses reported here, we have refined and expanded his description. We present protocols using barley (Hordeum vulgare) leaves, as described by Ross and used extensively in research, as well as radish (Raphanus sativus) cotyledons and mustard (Brassica juncea) seedlings; instructors will find published research on many other species. Student investigations could explore other species or tissues. BACKGROUND INFORMATION ON NITRATE REDUCTASE

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Nitrate reductase regulation: Effects of nitrate and light on nitrate reductase mRNA accumulation

Cited by 116 publications

References 34 publications

Induction of Nitrate Assimilatory Enzymes in the Tree Betula pendula

Induction of Nitrate Assimilatory Enzymes in the Tree Betula pendula

5[prime] Proximal Regions of Arabidopsis Nitrate Reductase Genes Direct Nitrate-Induced Transcription in Transgenic Tobacco

Nitrate reductase: A model system for the investigation of enzyme induction in eukaryotes

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