Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published December 1974 | Published
Journal Article Open

Characterization of Escherichia coli Flagellar Mutants That Are Insensitive to Catabolite Repression

Abstract

In Escherichia coli, the synthesis of the flagellar organelle is sensitive to catabolite repression. Synthesis requires the presence of the cyclic adenosine monophosphate receptor protein (Crp) and 3′,5′-cyclic adenosine monophosphate (cAMP); i.e., mutants that lack Crp or adenylcyclase (Cya) synthesize no flagella. We isolated and characterized a series of mutants (cfs) that restored flagella-forming ability in a Crp strain of E. coli. The mutations in these strains were transferred onto episomes and they were then introduced into a variety of other strains. The presence of the mutation resulted in flagella synthesis in Cya and Crp strains as well as in the wild type grown under conditions of catabolite repression. Deletion analysis and other genetic studies indicated that: (i) the cfs mutations had a dominant effect when they were in the transconfiguration in merodiploids: (ii) they occurred in or very close to the flaI gene: and (iii) their expression required the presence of an intact flaI gene adjacent to the cfs mutation. Biochemical studies showed that the synthesis of at least two flagellar polypeptides, the hook subunit and an amber fragment of flagellin, were absent in strains that carried a cya mutation. Their synthesis was depressed in strains grown under conditions of catabolite repression. The presence of the cfs mutation restored the specific synthesis of these two polypeptides. We suggest that the formation of the flaI gene product is the step in flagellar synthesis that is catabolite sensitive and requires cAMP. We propose a regulatory function for the product of the flaI gene.

Additional Information

© 1974 American Society for Microbiology. Received for publication 16 September 1974. We wish to express our appreciation to Laura Hofstadter, Marcia Hilmen, and Judy Jessup for their assistance with this project. M. Silverman was supported by funds from the Cancer Coordinating Committee of the University of California, San Diego. This investigation was supported by a research grant GB-15655 from the National Science Foundation.

Attached Files

Published - SILjbact74a.pdf

Files

SILjbact74a.pdf
Files (1.8 MB)
Name Size Download all
md5:054320ecef6d520cdf85cf41e186aefd
1.8 MB Preview Download

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023