Transcriptional analysis of the flagellar regulon of Salmonella typhimurium

Kutsukake, Kazuhiro; Ohya, Yoshikazu; Iino, Tetsuo

doi:10.1128/jb.172.2.741-747.1990

Cited by 382 publications

(393 citation statements)

References 39 publications

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“…In addition, it also plays a central role in flagellum assembly, as it acts as a checkpoint for late motility gene transcription (2,14,30). In several bacterial species, including the spirochete T. denticola, inactivation of flgE results in a failure to complete flagellum filament synthesis (34,36,39,55). In the studies reported here, we found that inactivation of flgE resulted in cells that were nonmotile and deficient in PFs.…”

Section: Discussionsupporting

confidence: 48%

“…4b) transcripts in SC-E1 were similar to those in the wild type. These results differ from those obtained for other bacteria, in which inhibition of hook protein synthesis results in the cessation of flagellin transcription (3,34,36). Thus, in B. burgdorferi, completion of the PF hook is not a checkpoint for transcriptional control of PF synthesis.…”

Section: Isolation Of the Sc-e1 Mutantcontrasting

confidence: 55%

“…In the absence of cascade control of motility gene transcription, B. burgdorferi appears to rely exclusively on translational control of its motility genes. Finally, as found in many other species of bacteria, mutation of flgE results in inhibition of the expression of chemotaxis genes (16,34,36). These genes are generally the last genes transcribed in the cascade.…”

Section: Discussionmentioning

confidence: 99%

“…In most bacteria, mutants that do not form the flagellar hook are deficient in flagellar filament proteins (3,34,36,39,55). Accordingly, we used Western blot analyses to monitor the accumulation of the major FlaB PF filament protein (41 kDa) and the minor FlaA filament proteins (37 and 38 kDa) (21) in SC-E1.…”

Section: Isolation Of the Sc-e1 Mutantmentioning

confidence: 99%

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Borrelia burgdorferi Uniquely Regulates Its Motility Genes and Has an Intricate Flagellar Hook-Basal Body Structure

et al. 2008

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Borrelia burgdorferi is a flat-wave, motile spirochete that causes Lyme disease. Motility is provided by periplasmic flagella (PFs) located between the cell cylinder and an outer membrane sheath. The structure of these PFs, which are composed of a basal body, a hook, and a filament, is similar to the structure of flagella of other bacteria. To determine if hook formation influences flagellin gene transcription in B. burgdorferi, we inactivated the hook structural gene flgE by targeted mutagenesis. In many bacteria, completion of the hook structure serves as a checkpoint for transcriptional control of flagellum synthesis and other chemotaxis and motility genes. Specifically, the hook allows secretion of the anti-sigma factor FlgM and concomitant late gene transcription promoted by 28 . However, the control of B. burgdorferi PF synthesis differs from the control of flagellum synthesis in other bacteria; the gene encoding 28 is not present in the genome of B. burgdorferi, nor are any 28 promoter recognition sequences associated with the motility genes. We found that B. burgdorferi flgE mutants lacked PFs, were rod shaped, and were nonmotile, which substantiates previous evidence that PFs are involved in both cell morphology and motility. Although most motility and chemotaxis gene products accumulated at wild-type levels in the absence of FlgE, mutant cells had markedly decreased levels of the flagellar filament proteins FlaA and FlaB. Further analyses showed that the reduction in the levels of flagellin proteins in the spirochetes lacking FlgE was mediated at the posttranscriptional level. Taken together, our results indicate that in B. burgdorferi, the completion of the hook does not serve as a checkpoint for transcriptional regulation of flagellum synthesis. In addition, we also present evidence that the hook protein in B. burgdorferi forms a high-molecular-weight complex and that formation of this complex occurs in the periplasmic space.Borrelia burgdorferi, the causative agent of Lyme disease, is a spirochete with a characteristic flat-wave morphology (24, 25; for a review, see reference 12). As a result of their unusual morphology, B. burgdorferi and other spirochete species have a highly specialized ability that allows them to traverse viscous gellike media (8). This unique swimming ability enables these bacteria to penetrate into specific host connective tissues and ecological niches (43). The importance of motility as a virulence factor has been implicated in several spirochete species, including Treponema denticola (42), Brachyspira hyodysenteriae (54), Borrelia garinii (60), and B. burgdorferi (10, 56).Motility in B. burgdorferi is provided by bundles of between 7 and 11 periplasmic flagella (PFs) that are subterminally attached near the cell ends. These PFs extend inward along the cell cylinder beneath an outer membrane sheath (6,24,28,46). B. burgdorferi PFs have a structure similar to that of flagella of other bacteria; a PF is composed of a basal body, a hook, and a filament containing a single major ...

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Section: Discussionsupporting

confidence: 48%

Section: Isolation Of the Sc-e1 Mutantcontrasting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

Section: Isolation Of the Sc-e1 Mutantmentioning

confidence: 99%

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Borrelia burgdorferi Uniquely Regulates Its Motility Genes and Has an Intricate Flagellar Hook-Basal Body Structure

et al. 2008

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“…These operons are divided into three classes according to their order of expression [7]. The master operon in the highest class governs the expression of the rest by activating operons in the second class.…”

Section: Introductionmentioning

confidence: 99%

How Salmonella typhimurium measures the length of flagellar filaments

Keener

2006

Bull. Math. Biol.

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We present a mathematical model for the growth and length regulation of the filament of the flagellar motor of Salmonella Typhimurium. Under the assumption that the molecular constituents are translocated into the nascent filament by an ATP-ase and then move by molecular diffusion to the growing end, we find a monotonically decreasing relationship between speed and velocity of growth that is inversely proportional to length for large length. This give qualitative but not quantitative agreement with data of th evelocity of growth.We also propose that the length of filaments is "measured" by the rate of secretion of the σ 28 -antifactor FlgM, using negative feedback, and present a mathematical model of this regulatory network.

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Genetic and molecular analyses of the interaction between the flagellum-specific sigma and anti-sigma factors in Salmonella typhimurium.

et al. 1994

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More than 50 genes are required for flagellar formation and function in Salmonella typhimurium. According to the cascade model of flagellar regulon, the flagellar operons are divided into three classes, 1, 2, and 3, with respect to transcriptional hierarchy. FliA is an alternative sigma factor specific for transcription of the class 3 operons, while FlgM is an anti‐sigma factor which binds to FliA and prevents its association with RNA polymerase core enzyme. In the present study, we isolated a number of fliA mutants in which the altered FliA proteins become insensitive to inhibition by FlgM. Sequence analysis of their mutation sites revealed that most of them caused the amino acid substitutions in region 4 of the conserved amino acid sequences of sigma factors which lies near the C‐terminal end of FliA. Using a set of fliA deletion mutants in a high‐expression plasmid, we demonstrated that polypeptides containing the C‐terminal portion of FliA could titrate the intracellular FlgM protein resulting in derepression of the class 3 operons. This result indicates that the C‐terminal region of FliA contains the FlgM‐binding domain. This was confirmed by a chemical cross‐linking experiment with FlgM and truncated FliA proteins.

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Transcriptional analysis of the flagellar regulon of Salmonella typhimurium

Cited by 382 publications

References 39 publications

Borrelia burgdorferi Uniquely Regulates Its Motility Genes and Has an Intricate Flagellar Hook-Basal Body Structure

Borrelia burgdorferi Uniquely Regulates Its Motility Genes and Has an Intricate Flagellar Hook-Basal Body Structure

How Salmonella typhimurium measures the length of flagellar filaments

Genetic and molecular analyses of the interaction between the flagellum-specific sigma and anti-sigma factors in Salmonella typhimurium.

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