Strength and Regulation of Seven rRNA Promoters in Escherichia coli.
The model prokaryote Escherichia coli contains seven copies of the rRNA operon in the genome. The presence of multiple rRNA operons is an advantage for increasing the level of ribosome, the key apparatus of translation, in response to environmental conditions. The complete sequence of E. coli genome...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2015-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC4696680?pdf=render |
| _version_ | 1811263233071251456 |
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| author | Michihisa Maeda Tomohiro Shimada Akira Ishihama |
| author_facet | Michihisa Maeda Tomohiro Shimada Akira Ishihama |
| author_sort | Michihisa Maeda |
| collection | DOAJ |
| description | The model prokaryote Escherichia coli contains seven copies of the rRNA operon in the genome. The presence of multiple rRNA operons is an advantage for increasing the level of ribosome, the key apparatus of translation, in response to environmental conditions. The complete sequence of E. coli genome, however, indicated the micro heterogeneity between seven rRNA operons, raising the possibility in functional heterogeneity and/or differential mode of expression. The aim of this research is to determine the strength and regulation of the promoter of each rRNA operon in E. coli. For this purpose, we used the double-fluorescent protein reporter pBRP system that was developed for accurate and precise determination of the promoter strength of protein-coding genes. For application of this promoter assay vector for measurement of the rRNA operon promoters devoid of the signal for translation, a synthetic SD sequence was added at the initiation codon of the reporter GFP gene, and then approximately 500 bp-sequence upstream each 16S rRNA was inserted in front of this SD sequence. Using this modified pGRS system, the promoter activity of each rrn operon was determined by measuring the rrn promoter-directed GFP and the reference promoter-directed RFP fluorescence, both encoded by a single and the same vector. Results indicated that: the promoter activity was the highest for the rrnE promoter under all growth conditions analyzed, including different growth phases of wild-type E. coli grown in various media; but the promoter strength of other six rrn promoters was various depending on the culture conditions. These findings altogether indicate that seven rRNA operons are different with respect to the regulation mode of expression, conferring an advantage to E. coli through a more fine-tuned control of ribosome formation in a wide range of environmental situations. Possible difference in the functional role of each rRNA operon is also discussed. |
| first_indexed | 2024-04-12T19:41:05Z |
| format | Article |
| id | doaj.art-929e70089526462b934a335f79c702b1 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-04-12T19:41:05Z |
| publishDate | 2015-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-929e70089526462b934a335f79c702b12022-12-22T03:19:04ZengPublic Library of Science (PLoS)PLoS ONE1932-62032015-01-011012e014469710.1371/journal.pone.0144697Strength and Regulation of Seven rRNA Promoters in Escherichia coli.Michihisa MaedaTomohiro ShimadaAkira IshihamaThe model prokaryote Escherichia coli contains seven copies of the rRNA operon in the genome. The presence of multiple rRNA operons is an advantage for increasing the level of ribosome, the key apparatus of translation, in response to environmental conditions. The complete sequence of E. coli genome, however, indicated the micro heterogeneity between seven rRNA operons, raising the possibility in functional heterogeneity and/or differential mode of expression. The aim of this research is to determine the strength and regulation of the promoter of each rRNA operon in E. coli. For this purpose, we used the double-fluorescent protein reporter pBRP system that was developed for accurate and precise determination of the promoter strength of protein-coding genes. For application of this promoter assay vector for measurement of the rRNA operon promoters devoid of the signal for translation, a synthetic SD sequence was added at the initiation codon of the reporter GFP gene, and then approximately 500 bp-sequence upstream each 16S rRNA was inserted in front of this SD sequence. Using this modified pGRS system, the promoter activity of each rrn operon was determined by measuring the rrn promoter-directed GFP and the reference promoter-directed RFP fluorescence, both encoded by a single and the same vector. Results indicated that: the promoter activity was the highest for the rrnE promoter under all growth conditions analyzed, including different growth phases of wild-type E. coli grown in various media; but the promoter strength of other six rrn promoters was various depending on the culture conditions. These findings altogether indicate that seven rRNA operons are different with respect to the regulation mode of expression, conferring an advantage to E. coli through a more fine-tuned control of ribosome formation in a wide range of environmental situations. Possible difference in the functional role of each rRNA operon is also discussed.http://europepmc.org/articles/PMC4696680?pdf=render |
| spellingShingle | Michihisa Maeda Tomohiro Shimada Akira Ishihama Strength and Regulation of Seven rRNA Promoters in Escherichia coli. PLoS ONE |
| title | Strength and Regulation of Seven rRNA Promoters in Escherichia coli. |
| title_full | Strength and Regulation of Seven rRNA Promoters in Escherichia coli. |
| title_fullStr | Strength and Regulation of Seven rRNA Promoters in Escherichia coli. |
| title_full_unstemmed | Strength and Regulation of Seven rRNA Promoters in Escherichia coli. |
| title_short | Strength and Regulation of Seven rRNA Promoters in Escherichia coli. |
| title_sort | strength and regulation of seven rrna promoters in escherichia coli |
| url | http://europepmc.org/articles/PMC4696680?pdf=render |
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