title: Molecular analysis of the crenarchaeal flagellum.
abstract: The ability to move towards favourable conditions provides fundamental advantages to organisms. Interestingly, flagella as motility structures evolved independently in the bacterial and the archaeal kingdom. Whereas bacterial flagella have been intensively studied, our knowledge regarding the archaeal counterpart is mostly restricted to Euryarchaeota rather than crenarchaeal flagella. We therefore investigated the flagellar assembly system of the crenarchaeal model organism Sulfolobus acidocaldarius in vivo. Promoter studies and qRT-PCR analyses of the flagella gene cluster provided evidence that the expression of the fla genes was induced by tryptone starvation. Moreover, we confirmed presence of a secondary fla promoter within the flaB gene that regulates the transcription of downstream genes flaX-J. Markerless in-frame deletions for all fla genes encoded in the fla gene cluster were constructed. Western blot analysis of all fla deletion strains suggested hierarchical protein interactions during the archaeal flagella assembly. Moreover, functional analysis by thermomicroscopy revealed non-motile cells for each of the mutant strains. Electron micrographs demonstrated that lack of motility coincided with the loss of flagellar assembly. Thus we demonstrated that all seven fla genes are essential for crenarchaeal flagellum assembly and function.
authors.affiliation: Molecular Biology of Archaea, Max Planck Institute for terrestrial Microbiology, Karl-von-Frisch-Strasse 10, 35043 Marburg, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Lassak
authors.forename: Tomasz
authors.initials: T
authors.lastname: Neiner
authors.forename: Abhrajyoti
authors.initials: A
authors.lastname: Ghosh
authors.forename: Andreas
authors.initials: A
authors.lastname: Klingl
authors.forename: Reinhard
authors.initials: R
authors.lastname: Wirth
authors.forename: Sonja-Verena
authors.initials: SV
authors.lastname: Albers
mesh_terms: D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism; D005407:Flagella / Q000235:genetics* / Q000378:metabolism; D005408:Flagellin / Q000235:genetics / Q000378:metabolism; D019848:Gene Expression Regulation, Archaeal; D008969:Molecular Sequence Data; D016945:Sulfolobus acidocaldarius / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D019843:Archaeal Proteins; D005408:Flagellin