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Synthesis and Differential Turnover of the CYS3 Regulatory Protein of Neurospora crassa Are Subject to Sulfur Control
- Source :
- Journal of Bacteriology. 180:478-482
- Publication Year :
- 1998
- Publisher :
- American Society for Microbiology, 1998.
-
Abstract
- The transcription factor CYS3 of Neurospora crassa is a positive regulator of the sulfur regulatory circuit which contains many structural genes involved in sulfur metabolism. Expression and degradation of the CYS3 protein are precisely regulated in a sulfur-dependent manner. cys-3 expression was found to be fully repressed by high concentrations of methionine or inorganic sulfate present in the culture medium and to be derepressed when these favored sulfur sources were limited. cys-3 transcripts could be readily detected within 2 h after derepression, whereas the CYS3 protein was not found until after 4 h. CYS3 is stable, with a half-life greater than 4 h under low-sulfur conditions when it is required for cell growth. However, it is degraded relatively quickly when methionine or inorganic sulfate becomes available. Upon sulfur repression, cys-3 transcripts disappeared within 30 min with an estimated half-life of 5 min whereas CYS3 protein almost entirely disappeared in 1 h with a half-life of approximately 10 min. These results suggest that a selective elimination of CYS3 is a highly regulated process. Site-directed mutagenesis showed that Lys-105 of CYS3 is important for its instability. The change of this single residue from lysine to glutamine resulted in a prolonged half life of CYS3 and impaired responsiveness of CYS3 degradation to sulfur level changes.
- Subjects :
- Saccharomyces cerevisiae Proteins
Recombinant Fusion Proteins
Sulfur metabolism
Gene Expression
chemistry.chemical_element
Genetics and Molecular Biology
Microbiology
Neurospora crassa
Fungal Proteins
chemistry.chemical_compound
Methionine
RNA, Messenger
Molecular Biology
Derepression
Fungal protein
biology
Sulfates
Lysine
Structural gene
Cystathionine gamma-Lyase
RNA, Fungal
biology.organism_classification
Sulfur
DNA-Binding Proteins
Glutamine
Kinetics
Biochemistry
chemistry
Transcription Factors
Subjects
Details
- ISSN :
- 10985530 and 00219193
- Volume :
- 180
- Database :
- OpenAIRE
- Journal :
- Journal of Bacteriology
- Accession number :
- edsair.doi.dedup.....852a1c61add6e363e6eaffb3b1cf04bc