Association of a cGMP-binding activity with nuclei isolated from amoebae of Dictyostelium discoideum and Polysphondylium violaceum

Abstract

When vegetative and early slug stage amoebae of Dictyostelium discoideum or Polysphondylium violaceum were lysed by filter breakage in a nuclear isolation buffer not containing detergents, substantial levels of a cGMP-binding activity with slow-dissociation kinetics were detected. After fractionation by centrifugation, 50% or more of this binding activity was associated with isolated nuclei. In addition, with Polysphondylium cells, the fraction of stable, nuclear-associated binding activity appeared to increase during cell aggregation. These results support the idea that cGMP might function in the nucleus during early development.Key words: cGMP-binding activity, nuclear isolation, Dictyostelium discoideum, Polysphondylium violaceum.