The nitrite reductase-encoding gene (YNI1) from the yeast Hansenula polymorpha was isolated from a lambda EMBL3 H. polymorpha genomic DNA library, using as a probe a 481 bp DNA fragment from the gene of Aspergillus nidulans encoding nitrite reductase (niiA). An open reading frame of 3132 bp, encoding a putative protein of 1044 amino acids with high similarity with nitrite reductases from fungi, was located by DNA sequencing in the phages λNB5 and λJA13. Genes YNI1 and YNR1 (encoding nitrate reductase) are clustered, separated by 1700 bp. Northern blot analysis showed that expression of YNI1 and YNR1 is co-ordinately regulated; induced by nitrate and nitrite and repressed by sources of reduced nitrogen, even in the presence of nitrate. A mutant lacking nitrite reductase activity was obtained by deletion of the chromosomal copy of YNI1. The mutant does not grow in nitrate or in nitrite; it exhibits a similar level of transcription of YNR1 to the wild type, but the nitrate reductase enzymic activity is only about 50% of the wild type. In the presence of nitrate the Δyni1::URA3 mutant extrudes approx. 24 nmol of nitrite/h per mg of yeast (wet weight), about five times more than the wild type.
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July 1996
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Research Article|
July 01 1996
The genes YNI1 and YNR1, encoding nitrite reductase and nitrate reductase respectively in the yeast Hansenula polymorpha, are clustered and co-ordinately regulated
Nélida BRITO;
Nélida BRITO
1Departamento de Bioquímica y Biología Molecular, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Canarias, Spain
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Julio AVILA;
Julio AVILA
1Departamento de Bioquímica y Biología Molecular, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Canarias, Spain
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M. Dolores PEREZ;
M. Dolores PEREZ
1Departamento de Bioquímica y Biología Molecular, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Canarias, Spain
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Celedonio GONZALEZ;
Celedonio GONZALEZ
1Departamento de Bioquímica y Biología Molecular, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Canarias, Spain
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José M. SIVERIO
José M. SIVERIO
*
*To whom correspondence should be addressed.
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Publisher: Portland Press Ltd
Received:
December 01 1995
Revision Received:
February 29 1996
Accepted:
February 29 1996
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London © 1996
1996
Biochem J (1996) 317 (1): 89–95.
Article history
Received:
December 01 1995
Revision Received:
February 29 1996
Accepted:
February 29 1996
Citation
Nélida BRITO, Julio AVILA, M. Dolores PEREZ, Celedonio GONZALEZ, José M. SIVERIO; The genes YNI1 and YNR1, encoding nitrite reductase and nitrate reductase respectively in the yeast Hansenula polymorpha, are clustered and co-ordinately regulated. Biochem J 1 July 1996; 317 (1): 89–95. doi: https://doi.org/10.1042/bj3170089
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