Identical, independent, and opposing roles of ppGpp and DksA in Escherichia coli

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

The recent discovery that the protein DksA acts as a coregulator of genes controlled by ppGpp led us to investigate the similarities and differences between the relaxed phenotype of a ppGpp-deficient mutant and the phenotype of a strain lacking DksA. We demonstrate that the absence of DksA and ppGpp has similar effects on many of the observed phenotypes but that DksA and ppGpp also have independent and sometimes opposing roles in the cell. Specifically, we show that overexpression of DksA can compensate for the loss of ppGpp with respect to transcription of the promoters PuspA, PlivJ, and P rrnBP1 as well as amino acid auxotrophy, cell-cell aggregation, motility, filamentation, and stationary phase morphology, suggesting that DksA can function without ppGpp in regulating gene expression. In addition, ppGpp and DksA have opposing effects on adhesion. In the course of our analysis, we also discovered new features of the relaxed mutant, namely, defects in cell-cell aggregation and motility.

OriginalsprogEngelsk
TidsskriftJournal of Bacteriology
Vol/bind189
Udgave nummer14
Sider (fra-til)5193-5202
Antal sider10
ISSN0021-9193
DOI
StatusUdgivet - 1 jul. 2007
Eksternt udgivetJa

ID: 203861022