Bioinformatic prediction reveals posttranscriptional regulation of the chromosomal replication initiator gene dnaA by the attenuator sRNA rnTrpL in Escherichia coli
Autor: | Daniel Edelmann, Siqi Li, Jens Georg, Bork A. Berghoff, Elena Evguenieva-Hackenberg |
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Rok vydání: | 2020 |
Předmět: |
DNA Replication
Transcription Genetic Operon genetic processes Mutant Attenuator (genetics) Biology 03 medical and health sciences 0302 clinical medicine Bacterial Proteins Escherichia coli Overproduction Molecular Biology Gene 030304 developmental biology 0303 health sciences Escherichia coli Proteins Wild type Gene Expression Regulation Bacterial Cell Biology Chromosomes Bacterial DnaA Cell biology DNA-Binding Proteins 030220 oncology & carcinogenesis Transfer RNA health occupations RNA Small Untranslated bacteria Research Paper |
Zdroj: | RNA Biol |
ISSN: | 1555-8584 1547-6286 |
Popis: | DnaA is the initiator protein of chromosome replication, but the regulation of its homoeostasis in enterobacteria is not well understood. The DnaA level remains stable at different growth rates, suggesting a link between metabolism and dnaA expression. In a bioinformatic prediction, which we made to unravel targets of the sRNA rnTrpL in Enterobacteriaceae, the dnaA mRNA was the most conserved target candidate. The sRNA rnTrpL is derived from the transcription attenuator of the tryptophan biosynthesis operon. In Escherichia coli, its level is higher in minimal than in rich medium due to derepressed transcription without external tryptophan supply. Overexpression and deletion of the rnTrpL gene decreased and increased, respectively, the levels of dnaA mRNA. The decrease of the dnaA mRNA level upon rnTrpL overproduction was dependent on hfq and rne. Base pairing between rnTrpL and dnaA mRNA in vivo was validated. In minimal medium, the oriC level was increased in the ΔtrpL mutant, in line with the expected DnaA overproduction and increased initiation of chromosome replication. In line with this, chromosomal rnTrpL mutation abolishing the interaction with dnaA increased both the dnaA mRNA and the oriC level. Moreover, upon addition of tryptophan to minimal medium cultures, the oriC level in the wild type was increased. Thus, rnTrpL is a base-pairing sRNA that posttranscriptionally regulates dnaA in E. coli. Furthermore, our data suggest that rnTrpL contributes to the DnaA homoeostasis in dependence on the nutrient availability, which is represented by the tryptophan level in the cell. |
Databáze: | OpenAIRE |
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