Simultaneous Coexpression ofBorrelia burgdorferiErp Proteins Occurs through a Specific,erpLocus-Directed Regulatory Mechanism

Abstract

An individual Borrelia burgdorferi bacterium can encode as many as 13 different Erp (OspE/F-related) proteins from mono-and bicistronic loci that are carried on up to 10 separate plasmids. We demonstrate through multilabel immunofluorescence analyses that individual bacteria simultaneously coexpress their entire Erp protein repertoire. While it has been proposed that B. burgdorferi controls expression of Erp and other plasmid-encoded proteins through changes in DNA topology, we observed regulated Erp expression in the absence of detectable differences in DNA supercoiling. Likewise, inhibition of DNA gyrase had no detectable effect on Erp expression. Furthermore, expression of loci physically adjacent to erp loci was observed to be independently regulated. It is concluded that Erp expression is regulated by a mechanism(s) directed at erp loci and not by a global, plasmid-wide mechanism.

Borrelia burgdorferi cp32 BpaB Modulates Expression of the Prophage NucP Nuclease and SsbP Single-Stranded DNA-Binding Protein

“…The nucP gene product likewise had not previously been functionally characterized. An earlier study by our laboratory gave this gene the placeholder name bppA (Borrelia plasmid protein A) (23). Subsequent Blast-P analyses of the predicted gene product found modest similarities with some bacteriophage-encoded nucleases (e.g., an E value of 10 5 similarity to LHK-Exo exonuclease of Laribacter hongkongensis) (62).…”

Immune evasion of Borrelia burgdorferi: mapping of a complement‐inhibitor factor H‐binding site of BbCRASP‐3, a novel member of the Erp protein family

“…Erp proteins are major candidates for surface proteins interacting with the immune system of the host. Along these lines, it was demonstrated that erp genes are transcribed during all stages at which spirochetes encounter host's serum [30] and multiple different Erp proteins are simultaneously expressed on the bacterial surface [31,32]. Thus, the ability to bind complementinhibiting factors, such as factor H and FHL-1, seems critical for immune evasion of the pathogen in a wide variety of hosts and this activity appears to be dependent on specific recognition motifs of individual Erp proteins.…”

Borrelia burgdorferi complement regulator-acquiring surface proteins (BbCRASPs): Expression patterns during the mammal–tick infection cycle

“…All the erp coding sequences, including erpA, erpC, and erpP, are preceded by almost identical 5′-non-coding sequences, including binding sites for at least 3 distinct DNA-binding proteins (Babb et al, 2004. Co-regulation of erp genes on different cp32 plasmids suggests the existence of similar molecular mechanisms that could coordinate expression of genes encoding BbCRASP-3, -4, and -5 at the transcriptional level Babb et al, 2001;El-Hage and Stevenson, 2002;Babb et al, 2004Babb et al, , 2006.…”