Roles of multiple flagellins in flagellar formation and flagellar growth post bdelloplast lysis in Bdellovibrio bacteriovorus.
Bdellovibrio bacteriovorus cells have a single polar flagellum whose helical pitch and diameter characteristically change near the midpoint, resulting in a tapered wave. There are six flagellin genes in the genome: fliC1 to fliC6. Accordingly, the flagellar filament is composed of several similar flagellin species. We have used knockout mutants of each gene and analyzed the mutational effects on the filament length and on the composition and localization of each flagellin species in the filament by electron microscopy and one- and two-dimensional polyacrylamide gel electrophoresis. The location and amounts of flagellins in a filament were determined to be as follows: a small amount of FliC3 at the proximal end, followed by a large amount of FliC5, a large amount of FliC1, a small amount of FliC2 in this order, and a large amount of FliC6 at the distal end. FliC4 was present at a low level, but the location was not determined. Filament lengths of newly born progeny cells increased during prolonged incubation in nutrient-deficient buffer. The newly formed part of the elongated filament was composed of mainly FliC6. Reverse transcription PCR analysis of flagellar gene expression over 5 days in buffer showed that fliC gene expression tailed off over 5 days in the wild-type cells, but in the fliC5 mutant, expression of the fliC2, fliC4, and fliC6 genes was elevated on day 5, suggesting that they may be expressed to compensate for the absence of a major component, FliC5.
Iida
Yoshiko
Y
Department of Life Sciences, Prefectural University of Hiroshima, 562 Nanatsuka, Shobara, Hiroshima 727-0023, Japan.
Hobley
Laura
L
Lambert
Carey
C
Fenton
Andrew K
AK
Sockett
R Elizabeth
RE
Aizawa
Shin-Ichi
S
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001501:Bdellovibrio / Q000737:chemistry / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D015180:Electrophoresis, Gel, Two-Dimensional; D005407:Flagella / Q000737:chemistry / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D005408:Flagellin / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D055786:Gene Knockout Techniques; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D016415:Sequence Alignment
D001426:Bacterial Proteins; D005408:Flagellin