Sohanpal, B.K. and Kulasekara, H.D. and Bonnen, A. and Blomfield, I.C. (2001) Orientational control of fimE expression in Escherichia coli. Molecular Microbiology, 42 (2). pp. 483-494.
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Phase-variable expression of type 1 fimbriae is, in part, controlled by site-specific DNA inversion of the fim switch in Escherichia coli. Of the two fim recombinases (FimB and FimE) that catalyse the inversion reaction, FimE exhibits a strong bias for phase switching from the ON to the OFF orientation. The specificity associated with fimE is the result of two different mechanisms: (i) FimE exhibits a preference for the invertible element in the ON orientation as substrate for recombination; (ii) the invertible element in the OFF orientation acts in cis to inhibit recombinase activity (orientational control). We show here that the invertible element negatively regulates fimE, even though expression of a fimE-lacZYA transcriptional fusion is unaffected by orientational control. The fimE transcript extends into the invertible region and hence switch ON-specific and switch OFF-specific mRNA contain different sequences. Furthermore, we show that orientational control is suppressed by the insertion of a structured RNA (tRNA(Gly)) between fimE and the fim switch, indicating that the switch OFF-specific mRNA is inactivated by 3' to 5' degradation. Analysis of the fim switch reveals that it contains two inhibitory elements that exert orientational control independently.
|Divisions:||Faculties > Science Technology and Medical Studies > School of Biosciences > Biomedical Research Group|
|Depositing User:||Sue Davies|
|Date Deposited:||19 Dec 2007 17:44|
|Last Modified:||05 Sep 2011 23:19|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/16 (The current URI for this page, for reference purposes)|
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