Effect of 3':5'-cyclic GMP derivatives on the formation of Caulobacter surface structures.

Exogenous derivatives of 3':5'-cyclic GMP, 8-bromo- and N2,O2'-dibutyryl cyclic GMP, coordinately repress surface structure differentiation in Caulobacter crescentus. Growth in the presence of cyclic GMP derivatives resulted in the loss of flagella and pili formation and concomitant resistance to both DNA phage phiCbK and RNA phage phiCb5 infection without affecting growth rate, stalk formation, and equatorial cell division. The effect of cyclic GMP derivatives was shown to be the repression of synthesis of specific structural proteins. This effect could be reversed by exogenous N6,O2'-dibutyryl 3':5'-cyclic AMP, and mutants resistant to repression by cyclic GMP derivatives exhibited a pleiotropic phenotype affecting a cyclic AMP-mediated event.