Abstract
Biochemical responses to cold and osmotic stresses overlap because each decreases the availability of free water. Since RNA-binding proteins are known to accumulate following cold stress and play key roles in regulating transcription termination, the effect of osmotic stress on expression of RNA-binding proteins was examined. The transcript levels of four genes encoding RNA-binding proteins (rbpA, rbpB, rbpC and rbpD) were monitored in Anabaena sp. PCC 7120 cultures supplemented with ammonium ions or growing under nitrogen-fixing conditions. Steady-state transcript levels of all four genes increased transiently in response to a temperature shift from 30 to 20°C under both nitrogen regimes. Osmotic stress also enhanced rbpB, rbpC and rbpD gene expression in ammonium grown cultures. In the absence of a combined nitrogen source, osmotic stress repressed the short-term induction of rbp gene expression. The accumulation of RNA-binding proteins did not follow transcript levels, but remained high 24 h after stress initiation. It is concluded that nitrogen nutrition modulates the stress-responsive regulation of RNA-binding proteins in cyanobacteria, providing a potential mechanism to integrate environmental and developmental signals.
Original language | English (US) |
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Pages (from-to) | 203-210 |
Number of pages | 8 |
Journal | FEMS Microbiology Letters |
Volume | 227 |
Issue number | 2 |
DOIs | |
State | Published - Oct 24 2003 |
Externally published | Yes |
Keywords
- Anabaena 7120
- Cold stress
- Cyanobacterium
- Nitrogen fixation
- Osmotic stress
- RNA-binding protein
- Rbp
- Salt stress
- Transcription regulation
ASJC Scopus subject areas
- General Medicine