Coordinated modulation of multiple processes through phase variation of a c-di-GMP phosphodiesterase in Clostridioides difficile.

The opportunistic nosocomial pathogen Clostridioides difficile exhibits phenotypic heterogeneity through phase variation, a stochastic, reversible process that modulates expression. In C. difficile, multiple sequences in the genome undergo inversion through site-specific recombination.

Flagellum and toxin phase variation impacts intestinal colonization and disease development in a mouse model of infection.

is a major nosocomial pathogen that can cause severe, toxin-mediated diarrhea and pseudomembranous colitis. Recent work has shown that exhibits heterogeneity in swimming motility and toxin production through phase variation by site-specific DNA recombination. The recombinase RecV reversibly inverts the flagellar switch sequence upstream of the operon, leading to the ON/OFF expression of flagellum and toxin genes.

Micron-scale supramolecular myosin arrays help mediate cytoskeletal assembly at mature adherens junctions.

Epithelial cells assemble specialized actomyosin structures at E-Cadherin-based cell-cell junctions, and the force exerted drives cell shape change during morphogenesis. The mechanisms that build this supramolecular actomyosin structure remain unclear. We used ZO-knockdown MDCK cells, which assemble a robust, polarized, and highly organized actomyosin cytoskeleton at the zonula adherens, combining genetic and pharmacologic approaches with superresolution microscopy to define molecular machines required.