A tick gut protein with fibronectin III domains aids Borrelia burgdorferi congregation to the gut during transmission

• Published in: PLoS pathogens Vol. 10; no. 8; p. e1004278
• Main Authors: Narasimhan, Sukanya, Coumou, Jeroen, Schuijt, Tim J, Boder, Eric, Hovius, Joppe W, Fikrig, Erol
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.08.2014; Public Library of Science (PLoS)
• Subjects: Animals; Arthropod Proteins - metabolism; Biology and Life Sciences; Borrelia burgdorferi; Deoxyribonucleic acid; Disease Models, Animal; DNA; Enzyme-Linked Immunosorbent Assay; Fibronectins; Fibronectins - metabolism; Gene expression; Health aspects; Host-Parasite Interactions - physiology; Lyme disease; Lyme Disease - transmission; Medicine and Health Sciences; Mice; Microscopy; Microscopy, Confocal; Migration; Molecular Sequence Data; Molecular weight; Polymerase Chain Reaction; Proteins; R&D; Research & development; Research and Analysis Methods; Software; Ticks; Ticks - metabolism; Vaccines; Variance analysis
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1004278

Borrelia burgdorferi transmission to the vertebrate host commences with growth of the spirochete in the tick gut and migration from the gut to the salivary glands. This complex process, involving intimate interactions of the spirochete with the gut epithelium, is pivotal to transmission. We utilized a yeast surface display library of tick gut proteins to perform a global screen for tick gut proteins that might interact with Borrelia membrane proteins. A putative fibronectin type III domain-containing tick gut protein (Ixofin3D) was most frequently identified from this screen and prioritized for further analysis. Immunization against Ixofin3D and RNA interference-mediated reduction in expression of Ixofin3D resulted in decreased spirochete burden in tick salivary glands and in the murine host. Microscopic examination showed decreased aggregation of spirochetes on the gut epithelium concomitant with reduced expression of Ixofin3D. Our observations suggest that the interaction between Borrelia and Ixofin3D facilitates spirochete congregation to the gut during transmission, and provides a "molecular exit" direction for spirochete egress from the gut.