ROLE OF THE ESCHERICHIA-COLI FADR REGULATOR IN STASIS SURVIVAL AND GROWTH PHASE-DEPENDENT EXPRESSION OF THE USPA, FAD, AND FAB GENES

Citation
A. Farewell et al., ROLE OF THE ESCHERICHIA-COLI FADR REGULATOR IN STASIS SURVIVAL AND GROWTH PHASE-DEPENDENT EXPRESSION OF THE USPA, FAD, AND FAB GENES, Journal of bacteriology, 178(22), 1996, pp. 6443-6450
Citations number
29
Categorie Soggetti
Microbiology
Journal title
ISSN journal
00219193
Volume
178
Issue
22
Year of publication
1996
Pages
6443 - 6450
Database
ISI
SICI code
0021-9193(1996)178:22<6443:ROTEFR>2.0.ZU;2-C
Abstract
The increased expression of the uspA gene of Escherichia coli is an es sential part of the cell's response to growth arrest, We demonstrate t hat stationary-phase activation of the uspA promoter is in part depend ent on growth phase-dependent inactivation or repression of the FadR r egulator, Transcription of uspA is derepressed during exponential grow th in fadR null mutants or by including the fatty acid oleate in the g rowth medium of FadR(+) cells, The results of DNA footprinting analysi s show that FadR binds downstream of the uspA promoter in the noncodin g region, Thus, uspA is a member of the fadR regulon, All the fad-lacZ fusions examined (fadBA, fadL, and fadD) are increasingly expressed i n stationary phase with kinetics similar to that of the increased expr ession of uspA. In contrast, beta-galactosidase levels decrease during stationary phase in a fabA-lacZ lysogen, consistent with the role of FadR as an activator of fabA. The growth phase-dependent increased and decreased transcription of fad genes and fabA, respectively, is depen dent on the status of the fadR gene, Cells carrying a mutation in the FadR gene (fadRS219N) that makes it nonderepressible exhibit a weak st ationary-phase induction of uspA and fad genes, In addition, cells car rying fadRS219N sun ive long-term stasis poorly, indicating that FadR- dependent alterations in fatty acid metabolism are an integral and imp ortant part of the adaptation to stationary phase.