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rdf:type |
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lifeskim:mentions |
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pubmed:dateCreated |
1994-3-23
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pubmed:abstractText |
Ammonium, or a metabolite of ammonium, represses the expression of nitrate reductase (NR) in Chlorella vulgaris. The removal of ammonium and addition of nitrate (induction) resulted in a rapid (20 min) peaked synthesis of NR mRNA. Nitrate reductase protein and activity increased at a much lower rate, reaching their maxima by 8 h. Ammonium added to nitrate-grown cells resulted in a dramatic decrease in NR mRNA from a steady-state level to undetectable levels within 15 min of ammonium addition. Nitrate reductase activity and protein levels decreased to 20% and 40% of initial levels respectively over 8 h. The half-life for NR mRNA under these conditions was estimated to be less than 5 min, compared with 120 min for NR protein. Such rapid decreases in NR mRNA suggested a degradation and/or cessation in NR mRNA transcription. No apparent difference in NR mRNA-specific RNAase activity of crude cell extracts (NR-induced or repressed) was observed. However, a significant difference in the susceptibility to degradation of NR mRNA from long-term nitrate-grown cells compared with the NR mRNA isolated from short-term induced cells (20 min in nitrate) was observed. NR mRNA isolated from long-term-nitrate-grown cells was completely degraded by RNAases in cell extracts under conditions in which the NR mRNA isolated from short-term induced cells was resistant to degradation. These results suggest that mRNA stability may be an important factor in the metabolic regulation of assimilatory nitrate reductase in Chlorella.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-1371579,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-1371867,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-1532580,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-1542684,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-16593758,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-16666423,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-16666879,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-16668575,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-16746764,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-1675424,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-17193712,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-1731978,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-1732744,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-1748677,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-1829499,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-1883330,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-1920421,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-2088178,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-2102837,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-2133648,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-2235482,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-2802625,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-2916847,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-3015963,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-3393528,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-3569270,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-429277,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-4371477,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-5432063,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8110194-7226226
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Feb
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pubmed:issn |
0264-6021
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
1
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pubmed:volume |
297 ( Pt 3)
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
561-5
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pubmed:dateRevised |
2010-9-13
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pubmed:meshHeading |
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pubmed:year |
1994
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pubmed:articleTitle |
Possible role for mRNA stability in the ammonium-controlled regulation of nitrate reductase expression.
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pubmed:affiliation |
USF College of Medicine, Department of Biochemistry and Molecular Biology, Tampa, FL 33612.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, Non-P.H.S.,
Research Support, Non-U.S. Gov't
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