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Ehira, S.Ohmori, M.Sato, N.
Genome-wide expression analysis of the responses to nitrogen deprivation in the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120.
DNA Res. 2003 Jun 30;10(3):97-113.
PMID:12886952
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Abstract
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A heterocyst is a terminally differentiated cell of cyanobacteria which is specialized in dinitrogen fixation. Heterocyst differentiation in Anabaena sp. strain PCC 7120 is triggered by deprivation of combined nitrogen in the medium. Although various genes that are upregulated during heterocyst differentiation have been reported, most studies to date were limited to individual or a small number of genes. We prepared microarrays in collaboration with other members of the Anabaena Genome Project. Here we report on the genome-wide expression analysis of the responses to nitrogen deprivation in Anabaena. Many unidentified genes, as well as previously known genes, were found to be upregulated by nitrogen deprivation at various time points. Three main profiles of gene expression were found: genes expressed transiently at an early stage (1-3 hr) of nitrogen deprivation, genes expressed transiently at a later stage (8 hr), and genes expressed when heterocysts are formed (24 hr). We also noted that many of the upregulated genes were physically clustered to form 'expressed islands' on the chromosome. Namely, large, continuous genomic regions containing many genes were upregulated in a coordinated manner. This suggests a mechanism of global regulation of gene expression that involves chromosomal structure, which is reminiscent of eukaryotic chromatin remodelling. The possible implications of this global regulation are discussed.
MeSH terms
- Anabaena/genetics/*growth & development/metabolism
- Bacterial Proteins/genetics/*metabolism
- Culture Media
- *Gene Expression Regulation, Bacterial
- *Genome, Bacterial
- Nitrogen/*metabolism
- Nitrogen Fixation
- *Oligonucleotide Array Sequence Analysis
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Peter, E.Wallner, T.Wilde, A.Grimm, B.
Comparative functional analysis of two hypothetical chloroplast open reading frames (ycf) involved in chlorophyll biosynthesis from Synechocystis sp. PCC6803 and plants.
J Plant Physiol. 2011 Aug 15;168(12):1380-6. doi: 10.1016/j.jplph.2011.01.014. Epub 2011 Mar 8.
PMID:21388705
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Abstract
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Related Articles
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Gene Index
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Hypothetical chloroplast open reading frames (ycfs) are highly conserved and interspecifically occurring genes in plastomes of plants and algae with significant functions in gene expression and photosynthesis. However, the function of many ycfs is still in vain so that attention is directed to other chloroplast functions such as metabolism of co-factors, protein translocation and protection against abiotic stress. We provide a comprehensive functional description of ycf53 and ycf59, two genes involved in chlorophyll biosynthesis. While ycf59 encodes an essential enzymatic component of Mg protoporphyrin monomethylester cyclase, ycf53 encodes a posttranslational regulator of chlorophyll biosynthesis. Their roles in tetrapyrrole biosynthesis were compared by using cyanobacterial and plant mutants with modulated expression of these two genes. Our work provides indications for diverse effects of these homologous gene products in plants and cyanobacteria on tetrapyrrole biosynthesis and photosynthesis.
MeSH terms
- Biosynthetic Pathways
- Chlorophyll/*biosynthesis
- Chloroplasts/*genetics
- Esters/metabolism
- Gene Knockout Techniques
- Models, Biological
- Open Reading Frames/*genetics
- Phylogeny
- Plant Proteins/chemistry/metabolism
- Plants/enzymology/*genetics
- Protein Subunits/metabolism
- Protoporphyrins/metabolism
- Synechocystis/*genetics
- Tetrapyrroles/biosynthesis
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