RasA is required for Myxococcus xanthus development and social motility

Abstract

An insertion in the rasA gene entirely blocked developmental aggregation and sporulation in Myxococcus xanthus while also reducing swarm expansion on a 0.3% agar surface. Data presented here demonstrate that rasA is required for extracellular fibril formation and social gliding motility.

FIG. 1.

Physical organization of the M. xanthus chromosome in the rasA region. Open reading frames and predicted directions of transcription are represented by arrows.

FIG. 2.

Light microscopy images showing developmental progression of DK1622 (wild type) and VP1066 (rasA) cells on TPM (starvation) agar. Mid-exponential-phase cells were concentrated 10-fold to a density of 5 × 10⁹ CFU/ml and spotted onto TPM agar to induce development. Bar = 1 mm.

FIG. 3.

Swarm edge morphology of motility mutants on rich (Casitone-yeast extract) medium containing 0.3% agar. The strains and their genotypes are displayed within each light micrograph. See reference for equivalent A⁻ S⁺ pictures. Bar = 5 mm.