Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.7.1.2 (nitrate reductase)
 3,861 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nitrate reductase (NR) structural gene (nitA) of Volvox carteri has been cloned and characterized. There is a single copy of this gene in the genome, and RFLP (restriction-fragment length polymorphism) analysis assigns it to the previously defined nitA/chlR locus on linkage group IX, 20-30 cM from the two beta-tubulin-encoding loci. Determination of the 5871-nt sequence of the coding region of genomic clones, and comparisons to a cDNA sequence, revealed ten introns and eleven exons that encode a 864-aa polypeptide. Detailed comparisons with higher-plant and fungal NRs indicate that, whereas the aa sequence is strongly conserved within functional domains for the flavin adenine dinucleotide-, heme- and molybdenum-pterin cofactor-binding sites, substantial differences in the aa sequence occur in the N-terminal end and the two inter-domain regions. Two potential transcription start points 439 and 452 nt upstream from the start codon and a polyadenylation signal 355 nt downstream from the stop codon have been identified by primer-extension analysis and cDNA sequencing, respectively. Accumulation of the nitA transcript is both induced by nitrate and repressed by ammonium and urea: after the organism is transferred from ammonium to nitrate as the nitrogen source, a 3.6-kb NR transcript is readily detectable on Northern blots by 10 min, reaches maximum abundance by 30 min, and then rapidly declines to an intermediate level that is subsequently maintained. Substantial induction by nitrate is observed at the end of the dark portion of the daily light/dark cycle, but the inductive response peaks in the first hour of the light period.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The nitrate reductase-encoding gene of Volvox carteri: map location, sequence and induction kinetics. 139 26

Aspergillus niger transformation frequencies of up to 1,176 transformants per micrograms DNA were achieved using the plasmid vector pSTA10 containing the A. niger nitrate reductase structural gene. Analysis of genomic endonuclease cleaved DNA from nitrate utilising transformants by DNA hybridisation, showed that most integration events are as a result of homologous recombination. The niaD transformation system was used successfully for the introduction of the unselected Escherichia coli fusion genes lacZ, encoding beta-galactosidase, and uidA, for beta-glucuronidase, as well as the Neurospora crassa tub-2 gene, for beta-tubulin. pSTA10 was also capable of transforming niaD mutants of other filamentous fungi such as A.nidulans, A. oryzae and Penicillium chrysogenum.
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PMID:Improved transformation efficiency of Aspergillus niger using the homologous niaD gene for nitrate reductase. 279 Oct 35

Pulsed field gel electrophoresis experiments show that chromosomal length polymorphisms are produced during meiosis in the ascomycetous plant pathogen Leptosphaeria maculans. Homologues in tetrads of L. maculans were identified on the basis of their binding to chromosome-specific probes that included beta-tubulin, nitrate reductase, 18S ribosomal DNA and two Random Amplified Polymorphic DNA (RAPD) markers. Changes in size of homologues were followed during meiosis. Significant karyotype variation was evident due to the random assortment of parental homologues of different sizes. In most cases, the progeny had the same-sized homologues as the parents; however, in some instances novel-sized homologues were detected that varied in size from those of the parents by up to 50 kb. Our results are consistent with the hypothesis that these novel chromosomal length polymorphisms are produced by reciprocal recombination between parental homologous chromosomes of unequal sizes.
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PMID:Inheritance of chromosomal length polymorphisms in the ascomycete Leptosphaeria maculans. 777 48

In Chlamydomonas reinhardtii, the expression of the Nia1 gene encoding NAD(P)H nitrate reductase is controlled at the transcriptional level, positively by light and negatively by ammonium. Previous work has shown that the region -279 to +269 with respect to the start site of transcription was sufficient to confer regulated expression of a promoterless arylsulfatase (Ars) reporter gene. To understand the mechanisms underlying this regulation, the -279 to +2 sequence was analysed for the presence of ammonium-responsive elements using either pJD54 (promoterless Ars gene) or pJD100 (minimal beta-tubulin promoter-driven Ars gene). The region lying between -195 and -120 was shown to be dispensable. Essential responsive elements were found in four distinct regions between -231 and -219, -120 and -100, -76 and -65 and -33 and -8. Each of these sequences is required for maximal expression in the absence of ammonium and a conserved GGA/TAGGGT motif is present in two of these regions. Several deletions within the region -33 to -77 were shown to partially relieve the transformants from the negative effect of ammonium. These experiments demonstrate that Nia1 expression is promoted by at least four elements between -231 and -8 and suggest that part of the repression by ammonium takes place through a proximal element located in the -51 to -33 sequence.
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PMID:Identification of short promoter regions involved in the transcriptional expression of the nitrate reductase gene in Chlamydomonas reinhardtii. 1128 12

In Chlamydomonas reinhardtii, the expression of the Nia1 gene encoding NAD(P)H nitrate reductase is controlled at the transcriptional level, positively by light and nitrate and negatively by ammonium. The sequences lying between positions -247 and -25 with respect to the start site of transcription were analyzed for the presence of regulatory elements using an arylsulfatase reporter gene ( Ars) fused to a minimal beta-tubulin promoter. An 84-bp sequence resulting from the joining of two partially homologous regions (-231 to -201 and -77 to -25) was shown to be necessary and sufficient to ensure activation and repression of the reporter gene. Interestingly, this shortened construct overexpressed the Ars gene in cells grown in nitrate-containing medium, relative to the construct bearing the complete -247 to -25 sequence. The 223-bp sequence was subjected to linker-scan analyses in the two regions of interest (-231 to -201 and -77 to -25). Most mutations introduced into this 84-bp sequence were shown to affect transcriptional activation on nitrate. Many of them also resulted in significantly increased arylsulfatase levels in cultures grown on ammonium. We therefore propose that the two regions act as bifunctional elements, stimulating or inhibiting the activity of the Nia1 promoter depending on the nature of the nitrogen source.
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PMID:Two short regions of the promoter are essential for activation and repression of the nitrate reductase gene in Chlamydomonas reinhardtii. 1224 97