The extended promoters for two outer membrane lipoprotein genes of Borrelia spp. uniquely include a T-rich region.
OspA and B proteins of Borrelia burgdorferi and Vmp proteins of Borrelia hermsii are abundant outer membrane lipoproteins, whose expression varies with the environment. The genes for these proteins have the '-35' and '-10' elements of a sigma70-type promoter. Deletions of the promoters for these genes were analysed with a chloramphenicol acetyltransferase (CAT) reporter gene and plasmid constructs that were stably maintained in Escherichia coli or transiently transfected into B. burgdorferi. Reporter expression was measured as susceptibility of transformed E. coli cells to chloramphenicol and the CAT activity of E. coli and B. burgdorferi lysates in vitro. Presence of the '-10' element was essential for full activity in both B. burgdorferi and E. coli. Upstream of the '-35' elements of the ospAB and vmp promoters were tracts with Ts in 16 of 20 positions for B. burgdorferi and 18 of 20 positions for B. hermsii. Deletion of the T-rich region from the ospAB or vmp promoter caused a greater reduction of CAT activity in B. burgdorferi than in E. coli. The findings indicate that ospAB and vmp promoters are extended promoters with two parts: (i) a core region containing typical '-35' and '-10' elements and (ii) a unique T-rich region.
Departments of Microbiology and Molecular Genetics and Medicine, B240 Med Sci I, University of California Irvine, Irvine, CA 92697 4025, USA.
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D000942:Antigens, Bacterial; D000954:Antigens, Surface / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001426:Bacterial Proteins / Q000378:metabolism; D001428:Bacterial Vaccines; D001483:Base Sequence; D001665:Binding Sites; D001898:Borrelia / Q000235:genetics*; D015748:Borrelia burgdorferi Group / Q000235:genetics; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D034982:Integration Host Factors; D008074:Lipoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D016415:Sequence Alignment; D017384:Sequence Deletion; D012689:Sequence Homology, Nucleic Acid; D012808:Sigma Factor / Q000378:metabolism; D013045:Species Specificity; D013936:Thymidine / Q000032:analysis*
D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D004269:DNA, Bacterial; D034982:Integration Host Factors; D008074:Lipoproteins; C072045:OspA protein; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor; C120881:vmp protein, Borrelia; C077030:OspB protein, Borrelia burgdorferi; D015500:Chloramphenicol O-Acetyltransferase; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; D013936:Thymidine