T-POP array identifies EcnR and PefI-SrgD as novel regulators of flagellar gene expression.
The T-POP transposon was employed in a general screen for tetracycline (Tet)-induced chromosomal loci that exhibited Tet-activated or Tet-repressed expression of a fliC-lac transcriptional fusion. Insertions that activated flagellar transcription were located in flagellar genes. T-POP insertions that exhibited Tet-dependent fliC-lac inhibition were isolated upstream of the ecnR, fimZ, pefI-srgD, rcsB, and ydiV genes and in the flagellar gene flgA, which is located upstream of the anti-sigma(28) factor gene flgM. When expressed from the chromosomal P(araBAD) promoter, EcnR, FimZ, PefI-SrgD, and RcsB inhibited the transcription of the flagellar class 1 flhDC operon. YdiV, which is weakly homologous to EAL domain proteins involved in cyclic-di-GMP regulation, appears to act at a step after class 1 transcription. By using a series of deletions of the regulatory genes to try to disrupt each pathway, these regulators were found to act largely independently of one another. These results identify EcnR and PefI-SrgD as additional components of the complex regulatory network controlling flagellar expression.
Wozniak
Christopher E
CE
Department of Microbiology, University of Washington, Seattle, 98195, USA.
Lee
Changhan
C
Hughes
Kelly T
KT
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media; D004251:DNA Transposable Elements; D005407:Flagella / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D016254:Mutagenesis, Insertional / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D011401:Promoter Regions, Genetic; D012486:Salmonella typhimurium / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D001426:Bacterial Proteins; D003470:Culture Media; D004251:DNA Transposable Elements