The Caulobacter crescentus flaFG region regulates synthesis and assembly of flagellin proteins encoded by two genetically unlinked gene clusters

Schoenlein, Patricia V.; Lui, Jing; Gallman, Lilly S.; Ely, Bert

doi:10.1128/jb.174.19.6046-6053.1992

Cited by 18 publications

(29 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This result provides further evidence that the three beta flagellin genes encode 25-kDa flagellins. This result is consistent with previous observations that the alpha region deletion mutants SC507 and PC7810 produce 25-kDa flagellins but not the 27-or 29-kDa flagellin (25,34). …”

supporting

confidence: 83%

A Family of Six Flagellin Genes Contributes to the Caulobacter crescentus Flagellar Filament

Ely

Crymes

et al. 2000

J Bacteriol

View full text Add to dashboard Cite

The Caulobacter crescentus flagellar filament is assembled from multiple flagellin proteins that are encoded by six genes. The amino acid sequences of the FljJ and FljL flagellins are divergent from those of the other four flagellins. Since these flagellins are the first to be assembled in the flagellar filament, one or both might have specialized to facilitate the initiation of filament assembly.Caulobacter crescentus is a dimorphic bacterium that differentiates as part of its normal cell cycle. Each cell division results in a stalked cell and a motile swarmer cell. The swarmer cell has a single flagellum at one pole that is responsible for motility. The flagellum is similar in structure to enteric flagella except that the filament is composed of multiple flagellin proteins (6,10,21,35,38). The hook-proximal portion of the flagellar filament consists of a 60-nm segment containing a 29-kDa flagellin (6). The next segment is 1 to 2 m in length and consists of a 27-kDa flagellin along with increasing amounts of a 25-kDa flagellin at its distal end. The remaining 2 to 10 m of the filament contains the 25-kDa flagellin. Thus, the flagellar filament consists of at least three different flagellar proteins in a precise arrangement.In addition to the three flagellins found in the filament, stationary-phase wild-type cells and some flagellar mutants synthesize a 22-kDa flagellin (15, 34). The 22-kDa flagellin is not found in functional flagellar filaments and may result from improper processing of the 25-kDa flagellin (22,34).Multiple flagellin genes have been identified in two unlinked clusters in the C. crescentus genome (11, 34). The alpha gene cluster includes the fljJ, fljK, and fljL genes that encode the 29-, 25-, and 27-kDa flagellins, respectively. The gene order in this region is flaY-flaE-fljJ-fljK-fljL-flaF-flbT-flBA-flaG (30, 32). Thus, the alpha cluster of flagellin genes is embedded in a cluster of other flagellar genes. The beta flagellin gene cluster is approximately 1,000 kb from the alpha cluster (8). No other flagellar genes are present at this locus.The flagellin gene family. We determined the nucleotide sequences of five of the six flagellin genes in the alpha (fljK and fljL) and beta (fljM, fljN, and fljO) regions using the plasmids described in Table 1. The nucleotide sequence of the sixth gene, fljJ, had been determined previously (11), and errors in this sequence were corrected using nucleotide sequence information produced by The Institute for Genome Research. Each region encodes a set of three independently transcribed flagellin genes. A comparison of these sequences to the C. crescentus genome sequence being produced by The Institute for Genome Research indicated that no additional flagellin genes were present elsewhere in the genome. Thus, C. crescentus has six flagellin genes in two clusters of three genes.To facilitate comparison of members of the flagellin gene family, the nucleotide sequences of the flagellin genes were aligned. There were 455 variable sites in the 822-bp sequence.Most of...

show abstract

supporting

confidence: 83%

A Family of Six Flagellin Genes Contributes to the Caulobacter crescentus Flagellar Filament

Ely

Crymes

et al. 2000

J Bacteriol

View full text Add to dashboard Cite

show abstract

“…In all cases, the levels of ␤-galactosidase activity in the double mutants were less than 10% of that in the wild-type fla ϩ strain, which is the regulated phenotype of a class III mutant. Thus flaR, flaA, and flaG must function in flagellum biosynthesis in a step after the posttranscriptional regulation by class III genes, a conclusion supported by the observation that flaG is involved either in a flagellin processing pathway or assembly of the flagellar filament (16,40).…”

Section: Regulation Of Fljk-lacz and Fljl-lacz Transcription Fusionsmentioning

confidence: 84%

“…Another group of fla genes has not yet been assigned within in the hierarchy, but these unclassified genes ( Fig. 1) have been shown to regulate expression of the class IV fljK and fljL flagellin genes or assembly of the flagellin proteins into the flagellar filament (16,40).…”

mentioning

confidence: 99%

Posttranscriptional regulation of Caulobacter flagellin genes by a late flagellum assembly checkpoint

Anderson

Newton

1997

J Bacteriol

View full text Add to dashboard Cite

Flagellum formation inThe stalked cell of the dimorphic bacterium Caulobacter crescentus divides repeatedly and asymmetrically to generate two functionally and structurally distinct progeny cells, an old nonmotile stalked cell and a new motile swarmer. The swarmer cell carries surface structures at one cell pole that are sequentially assembled during the course of the previous cell cycle. One of these structures is the flagellum; as in the flagella of enteric bacteria, it is composed of the basal body, which is embedded in the cell envelope, and the external hook and flagellar filament (reviewed in reference 20). The flagellum is assembled from the inside of the cell to the outside of the cell, and in C. crescentus the order of assembly corresponds generally to order of flagellar (fla) gene expression during the cell cycle (reviewed in references 4, 11, and 30

show abstract

“…1B). With the exception of the 25 kDa flagellin gene, which is present in multiple copies (Schoenlein et al, 1992), deletion of any one of the flagellin genes results in reduced motility (Minnich et al, 1988).…”

Section: Flagellum Structure and Assemblymentioning

confidence: 99%

Regulation of the Caulobacter flagellar gene hierarchy; not just for motility

Newton

1997

Molecular Microbiology

107

102

View full text Add to dashboard Cite

SummaryThe Caulobacter crescentus flagellum serves not only as a motility apparatus, but also as a key landmark in the differentiation of this asymmetrically dividing bacterium. A distinctive aspect of flagellum biosynthesis is the periodic expression of the flagellar genes during the cell cycle in a sequence corresponding to the order of gene product assembly into the growing flagellum. This program of gene expression is achieved in part by the organization of flagellar genes into a four-tiered regulatory hierarchy that controls their expression at both the transcriptional and post-transcriptional levels. Because of the close interconnection of the developmental program to the asymmetric celldivision cycle in C. crescentus, studies of flagellar gene regulation and motility have also begun to reveal basic mechanisms responsible for control of the cell cycle itself. Here, we review recent work on regulation of the flagellar gene hierarchy in C. crescentus and consider regulatory mechanisms that are distinct from those described in Escherichia coli and Salmonella typhimurium.

show abstract

The Caulobacter crescentus flaFG region regulates synthesis and assembly of flagellin proteins encoded by two genetically unlinked gene clusters

Cited by 18 publications

References 31 publications

A Family of Six Flagellin Genes Contributes to the Caulobacter crescentus Flagellar Filament

A Family of Six Flagellin Genes Contributes to the Caulobacter crescentus Flagellar Filament

Posttranscriptional regulation of Caulobacter flagellin genes by a late flagellum assembly checkpoint

Regulation of the Caulobacter flagellar gene hierarchy; not just for motility

Contact Info

Product

Resources

About