UNBALANCED MEMBRANE PHOSPHOLIPID COMPOSITIONS AFFECT TRANSCRIPTIONAL EXPRESSION OF CERTAIN REGULATORY GENES IN ESCHERICHIA-COLI

Citation
K. Inoue et al., UNBALANCED MEMBRANE PHOSPHOLIPID COMPOSITIONS AFFECT TRANSCRIPTIONAL EXPRESSION OF CERTAIN REGULATORY GENES IN ESCHERICHIA-COLI, Journal of bacteriology, 179(9), 1997, pp. 2872-2878
Citations number
60
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
ISSN journal
0021-9193
Volume
179
Issue
9
Year of publication
1997
Pages
2872 - 2878
Database
ISI
SICI code
0021-9193(1997)179:9<2872:UMPCAT>2.0.ZU;2-T
Abstract
The amount of porin protein OmpF in the outer membrane of Escherichia coli was reduced to one-third bu the pgsA3 mutation that diminishes th e amount of phosphatidylglycerol and cardiolipin in the membrane, wher eas a cls (cardiolipin synthase) null mutation had no effect, Osmoregu lation of OmpF was functional in the pgsA3 mutant. As assessed by the beta-galactosidase activities of lacZ fusions, the ompF expression was not reduced at the transcriptional level but was reduced about threef old at the posttranscriptional Level by pgsA3. This reduction was most ly restored by a micF null mutation, and the micF RNA that inhibits th e ompF mRNA translation was present 1.3 to 1,4 times more in the pgsA3 mutant, as assayed by RNase protection and Northern blot analyses. El evation of the level of micF RNA was not restricted to acidic:phosphol ipid deficiency: OmpP was hardly detected and micF RNA was present 2.7 to 2.8 times more in a pssA null mutant that lacked phosphatidylethan olamine, Other common phenotypes of pgsA3 and pssA null mutants, reduc ed rates of cell growth and phospholipid synthesis, were not the cause of micF activation, Salicylate, which activates micF expression and i nhibits cell motility, did not repress tile flagellar master operon, T hese results imply that an unbalanced phospholipid composition, rather than a decrease or increase in the amount of specific phospholipid sp ecies, induces a phospholipid-specific stress signal to which certain regulatory genes respond positively or negatively according to their i ntrinsic mechanisms.