title: Environmental factors affecting the expression of type IV pilus genes as well as piliation of Thermus thermophilus.
abstract: The thermophilic bacterium Thermus thermophilus HB27 is known for its highly efficient natural transformation system, which has become a model system to study the structure and function of DNA transporter in thermophilic bacteria. The DNA transporter is functionally linked to type IV pili (T4P), which are essential for twitching motility and adhesion to solid surfaces. However, the pilus structures themselves are dispensable for natural transformation. Here, we report that the cellular mRNA levels of the major structural subunit of the T4P, PilA4, are regulated by environmental factors. Growth of T. thermophilus in minimal medium or low temperature (55 °C) leads to a significant increase in pilA4 transcripts. In contrast, the transcript levels of the minor pilin pilA1 as well as other T4P genes are nearly unaffected. The elevated pilA4 mRNA levels are accompanied by an increase in piliation of the cells but not by elevated natural transformation frequencies. Hyperpiliation leads to increased adhesion to plastic surfaces. The increased cell-surface interactions are suggested to represent an adaptive response to temperature stress and may be advantageous for survival of T. thermophilus.
authors.affiliation: Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Salzer
authors.forename: Timo
authors.initials: T
authors.lastname: Kern
authors.forename: Friederike
authors.initials: F
authors.lastname: Joos
authors.forename: Beate
authors.initials: B
authors.lastname: Averhoff
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D001692:Biological Transport / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004777:Environment; D010861:Fimbriae, Bacterial / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D013696:Temperature; D016963:Thermus thermophilus / Q000235:genetics*; D014169:Transformation, Bacterial / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012333:RNA, Messenger
keywords: DNA translocator; Thermus thermophilus; gene regulation; natural competence; type IV pili