Flavobacterium johnsoniae gldN and gldO Are Partially Redundant Genes Required for Gliding Motility and Surface Localization of SprB

Abstract

Cells of the gliding bacterium Flavobacterium johnsoniae move rapidly over surfaces. Mutations in gldN cause a partial defect in gliding. A novel bacteriophage selection strategy was used to aid construction of a strain with a deletion spanning gldN and the closely related gene gldO in an otherwise wild-type F. johnsoniae UW101 background. Bacteriophage transduction was used to move a gldN mutation into F. johnsoniae UW101 to allow phenotypic comparison with the gldNO deletion mutant. Cells of the gldN mutant formed nonspreading colonies on agar but retained some ability to glide in wet mounts. In contrast, cells of the gldNO deletion mutant were completely nonmotile, indicating that cells require GldN, or the GldN-like protein GldO, to glide. Recent results suggest that Porphyromonas gingivalis PorN, which is similar in sequence to GldN, has a role in protein secretion across the outer membrane. Cells of the F. johnsoniae gldNO deletion mutant were defective in localization of the motility protein SprB to the cell surface, suggesting that GldN may be involved in secretion of components of the motility machinery. Cells of the gldNO deletion mutant were also deficient in chitin utilization and were resistant to infection by bacteriophages, phenotypes that may also be related to defects in protein secretion.

Helical flow of surface protein required for bacterial gliding motility

“…Wild-type cells moved rapidly on glass surfaces, whereas cells of an sprB deletion mutant exhibited little net movement, as previously observed (19), suggesting that SprB has an important role in motility. Addition of antisera against SprB weakened the ability of wild-type cells to bind to and move on glass (Fig.…”

Flavobacterium johnsoniae RemA Is a Mobile Cell Surface Lectin Involved in Gliding

“…All other deletion strains listed in Table 1 except for CJ2089 [rpsL2 ⌬(gldN gldO) remA::myc-tag-1] and CJ2090 [rpsL2 ⌬(gldN gldO)] were constructed in the same way, using the primers listed in Table S1 in the supplemental material and the plasmids listed in Table 1. CJ2089 and CJ2090 were constructed as previously described (33) by introducing pNap3 into CJ2083 or CJ1827, respectively, selecting for antibiotic-resistant colonies that had the plasmid inserted in the genome and then selecting for resistance to Cj1 to obtain the gldNO deletions. The sprF mutant CJ2097 was constructed by integration of pRR47, which carries an internal fragment of sprF, into the chromosome of CJ2083 essentially as previously described (31).…”

“…SprB is a cell surface protein that appears to be propelled rapidly by the motility machinery (26). Some of the motility proteins (GldK, GldL, GldM, GldN, SprA, SprE, and SprT) are thought to comprise a protein secretion system, the PorSS, that is needed for delivery of SprB to the cell surface and for secretion of an extracellular chitinase (33)(34)(35). The PorSS is not related to the type I to type VI protein secretion systems.…”

“…Completely nonmotile gld mutants are resistant to infection by all bacteriophages, whereas most mutants with partial motility defects are resistant to some but not all phages (33). sprB mutants display increased resistance to F. johnsoniae phages Cj1, Cj13, Cj23, and Cj29 but are sensitive to Cj28, Cj42, Cj48, and Cj54 (26).…”

The Screw-Like Movement of a Gliding Bacterium Is Powered by Spiral Motion of Cell-Surface Adhesins

“…Although the mechanism for gliding is barely understood, we know that Flavobacterium johnsoniae, which exhibits some of the fastest gliding of all known bacteria, has a powerful rotary motor (8) and a mobile cell-surface adhesin, SprB (9)(10)(11). Proteins of the type IX secretion system, which are abundant in gliding bacteria related to Flavobacterium, are required for secretion of SprB to the cell surface (12)(13)(14).…”