A NOVEL DICTYOSTELIUM-DISCOIDEUM GENE REQUIRED FOR CAMP-DEPENDENT CELL-AGGREGATION

Using a method of random insertional mutagenesis called REMI (restrict ion enzyme-mediated integration), we isolated two mutant strains of Di ctyostelium discoideum with a defect in cAMP-dependent cell aggregatio n. On bacterial lawns, both of the cells formed large and smooth plaqu es, When starved in a non-nutrient medium, they became elongated and e xtended pseudopods very frequently like starved wild type cells, Howev er, they never formed streams toward an aggregation center, Genomic DN A fragments flanking the sites of insertion of the REMI tag were rescu ed from the mutant cells, The fragments contained one common open read ing frame encoding a protein of 1148 amino acid residues, The protein' s sequence is homologous to those of two hypothetical proteins of S. c erevisiae and S. pombe. (C) 1998 Academic Press.