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| Status |
Public on Jan 30, 2014 |
| Title |
The omega subunit of the RNA polymerase core directs transcription efficiency in cyanobacteria |
| Organism |
Synechocystis sp. PCC 6803 |
| Experiment type |
Expression profiling by array
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| Summary |
The catalytic core of the RNA polymerase of most eubacteria is composed of two α subunits and β, β’ and ω subunits. In Escherichia coli, the ω subunit (encoded by the rpoZ gene) has been suggested to assist β’ during RNA polymerase core assembly. The function of the ω subunit is particularly interesting in cyanobacteria because the cyanobacterial β’ is split to N-terminal γ and C-terminal β’ subunits. The ∆rpoZ strain of the cyanobacterium Synechocystis sp. PCC 6803 grew well in standard conditions although the mutant cells showed low light-saturated photosynthetic activity, low Rubisco content and accumulated high quantities of protective carotenoids and α-tocopherol. The ∆rpoZ strain contained 15% less of the primary σ factor, SigA, than the control strain, and recruitment of SigA to the RNA polymerase core was inefficient in ∆rpoZ. Thus, a cyanobacterial RNA polymerase holoenzyme lacking the ω subunit contains less frequently the primary σ factor. A DNA microarray analysis revealed that this leads to specific down-regulation of highly expressed genes, like genes encoding subunits for Rubisco, ATP synthase, NADH-dehydrogenase and carbon concentrating mechanisms. On the contrary, many genes showing only low or moderate expression in the control strain were up-regulated in ∆rpoZ. A conserved -10 region was detected in promoters showing up or down-regulation in ∆rpoZ, but -35 regions of down-regulated genes completely differed from -35 regions of up-regulated genes.
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| Overall design |
Cells from cyanobacteria Synechocystis sp. PCC 6803 named as control strain (CS) and RNA polymerase omega subunit inactivation strain, ΔrpoZ, were harvested (A730=1, 40 mL) directly from standard growth conditions (continuous illumination at the PPFD of 40 µmol m-2s-1, 32°C, ambient CO2). From three to four independent experiments were performed at each conditions.
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| Contributor(s) |
Tyystjarvi T, Gunnelius L, Hakkila K, Matthijs HC |
| Citation(s) |
24476911 |
| Submission date |
Oct 24, 2013 |
| Last update date |
Oct 16, 2015 |
| Contact name |
Taina Tyystjarvi |
| E-mail(s) |
taityy@utu.fi
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| Organization name |
University of Turku
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| Department |
Biochemistry
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| Lab |
Molecular Plant Biology
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| Street address |
Pharmacity/Itäinen Pitkäkatu 4 C, 6th floor
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| City |
Turku |
| ZIP/Postal code |
20520 |
| Country |
Finland |
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| Platforms (1) |
| GPL17595 |
Agilent-016989 Synechocystis array [ORF version] |
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| Samples (7)
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| Relations |
| BioProject |
PRJNA224191 |
| Supplementary file |
Size |
Download |
File type/resource |
| GSE51647_RAW.tar |
5.3 Mb |
(http)(custom) |
TAR (of TXT) |
| Raw data provided as supplementary file |
| Processed data included within Sample table |
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