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Dissection of σ E ‐dependent cell lysis in Escherichia coli : roles of RpoE regulators RseA, RseB and periplasmic folding catalyst PpiD
Author(s) -
Noor Rashed,
Murata Masayuki,
Nagamitsu Hiroshi,
Klein Gracjana,
Raina Satish,
Yamada Mamoru
Publication year - 2009
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/j.1365-2443.2009.01318.x
Subject(s) - periplasmic space , biology , lysis , microbiology and biotechnology , cell , mutant , clone (java method) , escherichia coli , biochemistry , gene
To understand the mechanism of σ E ‐dependent cell lysis, we examined the consequences of deletion derivatives of rpoE regulators rseA , rseB and rseC on σ E transcription, on levels of free versus membrane‐bound σ E and on OMP‐biogenesis limiting factor(s) that could impact cell lysis. RT‐PCR showed that individual nonpolar Δ rseA and Δ rseB increased the rpoE expression to varying extents, with pronounced induction in Δ rseA . Significantly the ratio of soluble (free) versus membrane‐bound form of RpoE increased in Δ rseA , however without increase of its total amount, unraveling furthermore complexity in RpoE regulation. Significant characteristics of cell lysis, accompanied by a severe reduction in the levels of periplasmic OMP‐folding factor (PpiD), were observed in Δ rseA. The cell‐lysis phenotype of Δ rseA was suppressed by either rseA or ppiD plasmids, but neither by rseB nor by rseC clones. However, the cell lysis of the wild‐type strain was almost completely repressed not only by the rseA clone but also by the rseB clone, suggesting RseB might be limiting in vivo . Thus, increase in the ratio of free σ E in rseA mutants with a concomitant reduction in PpiD levels can account for σ E ‐dependent lysis in concert with a potential role of small RNAs on the lysis process.