Expression of the flagellin gene in Borrelia is controlled by an alternative sigma factor.
The flagellin genes from six Borrelia species were cloned, sequenced and characterized at the molecular level. The flagellin genes of two relapsing fever Borrelia species, B. hermsii and B. crocidurae, three Lyme disease genomic species, B. burgdorferi, B. afzelii and B. garinii, and the avian borreliosis agent, B. anserina, were compared and showed an 85-93% sequence identity to each other. Comparison of the fla genes from the different Lyme borreliosis spirochaetes revealed that they were 94-99% identical. Nucleotide sequencing of the fla gene and primer extension on isolated mRNA from both B. hermsii (as transcribed in Escherichia coli) and B. burgdorferi (as transcribed in the natural host) identified the putative transcriptional start points, the ribosomebinding sites and the promoter regions of these genes. The deduced promoter of the Borrelia flagellin gene resembled neither the sigma 70 promoter of prokaryotes, as seen for the genes for the outer-surface proteins A and B in Lyme disease Borrelia and the genes for the variable major proteins 7 and 21 of B. hermsii, nor the sigma 28 consensus promoter region of motility genes from other bacteria. Instead, the promoter of the fla gene in Borrelia has most similarity to the bacteriophage SP01 sigma gp33-34 promoter sequence of Bacillus subtilis.
Noppa
L
L
Department of Microbiology, Umeå University, Sweden.
Burman
N
N
Sadziene
A
A
Barbour
A G
AG
Bergström
S
S
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D005075:Biological Evolution; D001898:Borrelia / Q000235:genetics* / Q000378:metabolism; D015748:Borrelia burgdorferi Group / Q000235:genetics / Q000378:metabolism; D016384:Consensus Sequence; D017931:DNA Primers; D004926:Escherichia coli / Q000235:genetics; D005408:Flagellin / Q000096:biosynthesis / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D008193:Lyme Disease / Q000382:microbiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D012270:Ribosomes / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D012808:Sigma Factor / Q000378:metabolism*; D013045:Species Specificity; D014158:Transcription, Genetic
D017931:DNA Primers; D012333:RNA, Messenger; D012808:Sigma Factor; D005408:Flagellin