Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.3 (RNase III)
 1,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cyanobacteria are diverse photosynthetic microbes with the ability to convert CO2 into useful products. However, metabolic engineering of cyanobacteria remains challenging because of the limited resources for modifying the expression of endogenous and exogenous biochemical pathways. Fine-tuned control of protein production will be critical to optimize the biological conversion of CO2 into desirable molecules. Messenger RNAs (mRNAs) are labile intermediates that play critical roles in determining the translation rate and steady-state protein concentrations in the cell. The majority of studies on mRNA turnover have focused on the model heterotrophic bacteria Escherichia coli and Bacillus subtilis. These studies have elucidated many RNA modifying and processing enzymes and have highlighted the differences between these Gram-negative and Gram-positive bacteria, respectively. In contrast, much less is known about mRNA turnover in cyanobacteria. We generated a compendium of the major ribonucleases (RNases) and provide an in-depth analysis of RNase III-like enzymes in commonly studied and diverse cyanobacteria. Furthermore, using targeted gene deletion, we genetically dissected the RNases in Synechococcus sp. PCC 7002, one of the fastest growing and industrially attractive cyanobacterial strains. We found that all three cyanobacterial homologs of RNase III and a member of the RNase II/R family are not essential under standard laboratory conditions, while homologs of RNase E/G, RNase J1/J2, PNPase, and a different member of the RNase II/R family appear to be essential for growth. This work will enhance our understanding of native control of gene expression and will facilitate the development of an RNA-based toolkit for metabolic engineering in cyanobacteria.
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PMID:Genetic and genomic analysis of RNases in model cyanobacteria. 2559 45

Upon nitrogen deficiency, some filamentous cyanobacteria differentiate specialized cells, called heterocysts, devoted to N2 fixation. Heterocysts appear regularly spaced along the filaments and exhibit structural and metabolic adaptations, such as loss of photosynthetic CO2 fixation or increased respiration, to provide a proper microaerobic environment for its specialized function. Heterocyst development is under transcriptional control of the global nitrogen regulator NtcA and the specific regulator HetR. Transcription of a large number of genes is induced or repressed upon nitrogen deficiency specifically in cells undergoing differentiation. In recent years, the HetR regulon has been described to include heterocyst-specific trans-acting small RNAs and antisense RNAs (asRNAs), suggesting that there is an additional layer of post-transcriptional regulation involved in heterocyst development. Here, we characterize in the cyanobacterium Nostoc (Anabaena) sp. PCC 7120 an asRNA, that we call as_glpX, transcribed within the glpX gene encoding the Calvin cycle bifunctional enzyme sedoheptulose-1,7-bisphosphatase/fructose-1,6-bisphosphatase (SBPase). Transcription of as_glpX is restricted to heterocysts and is induced very early during the process of differentiation. Expression of as_glpX RNA promotes the cleavage of the glpX mRNA by RNase III, resulting in a reduced amount of SBPase. Therefore, the early expression of this asRNA could contribute to the quick shut-down of CO2 fixation in those cells in the filament that are undergoing differentiation into heterocysts. In summary, as_glpX is the first naturally occurring asRNA shown to rapidly and dynamically regulate metabolic transformation in Nostoc heterocysts. The use of antisense transcripts to manipulate gene expression specifically in heterocysts could became a useful tool for metabolic engineering in cyanobacteria.
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PMID:A Heterocyst-Specific Antisense RNA Contributes to Metabolic Reprogramming in Nostoc sp. PCC 7120. 3133 41