Regulated synthesis of the Borrelia burgdorferi inner-membrane lipoprotein IpLA7 (P22, P22-A) during the Lyme disease spirochaete's mammal-tick infectious cycle.

Abstract

Results of previous immunological studies suggested that Borrelia burgdorferi regulates synthesis of the IpLA7 lipoprotein during mammalian infection. Through combined use of quantitative reverse transcription PCR, immunofluorescence analyses, ELISA and immunoblotting, it is now demonstrated that IpLA7 is actually expressed throughout mammalian infection, as well as during transmission both from feeding ticks to naïve mice and from infected mice to naïve, feeding ticks. However, proportions of IpLA7-expressing B. burgdorferi within tick midguts declined significantly with time following completion of blood feeding. Cultured bacteria differentially expressed IpLA7 in response to changes in temperature, pH and concentration of 4,5-dihydroxy-2,3-pentanedione, the precursor of autoinducer 2, indicative of mechanisms governing IpLA7 expression. Previous studies also reported mixed results as to the cellular localization of IpLA7. It is now demonstrated that IpLA7 localizes primarily to the borrelial inner membrane and is not surface-exposed, consistent with the ability of these bacteria to produce IpLA7 throughout mammalian infection despite being the target of a robust immune response.

• Authors: Kate von Lackum, Kristina M Ollison, Tomasz Bykowski, Andrew J Nowalk, Jessica L Hughes, James A Carroll, Wolfram R Zückert, Brian Stevenson
• Journal: Microbiology (Reading, England) (Microbiology (Reading)) Vol. 153 Issue Pt 5 Pg. 1361-1371 (May 2007) ISSN: 1350-0872 [Print] England
• PMID: 17464050 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• 4,5-dihydroxy-2,3-pentanedione
• Bacterial Proteins
• Lipoproteins
• Membrane Proteins
• Pentanes
• RNA, Messenger

Topics

• Animals
• Bacterial Proteins (biosynthesis, genetics)
• Blotting, Western
• Borrelia burgdorferi (genetics, metabolism)
• Cell Membrane (chemistry)
• Disease Models, Animal
• Enzyme-Linked Immunosorbent Assay
• Female
• Gastrointestinal Tract (microbiology)
• Gene Expression Regulation, Bacterial
• Hydrogen-Ion Concentration
• Lipoproteins (biosynthesis, genetics)
• Lyme Disease (microbiology)
• Membrane Proteins (biosynthesis, genetics)
• Mice
• Mice, Inbred BALB C
• Microscopy, Fluorescence
• Pentanes (metabolism)
• RNA, Messenger (biosynthesis, genetics)
• Reverse Transcriptase Polymerase Chain Reaction
• Temperature
• Ticks (microbiology)