Expression and role of adenylyl cyclases during late development in Dictyostelium discoideum

Development in the social amoeba Dictyostelium discoideum is characterized by the formation of a multicellular structure with a well defined temporal and spatial pattern. Via the activation of cAMP receptors and protein kinas e A, cAMP signalling pathways are responsible for many developmentally regu lated gene expression events in the organism. cAMP acts as chemoattractant, as an extracellular morphogen and as intracellular messenger. Three adenyl yl cyclases have been described so far, ACA, ACG and ACB (Pitt et al., 1992 ; Meima and Schaap, 1999; Soderbom et al, 1999). Null mutants of these enzy mes show defects in aggregation, spore germination (Van Es et al, 1996) and terminal differentiation respectively. To elucidate their role in pattern formation in more detail we use LacZ-promotor constructs and in situ hybrid ization to compare the wild type pattern with some of the adenylyl cyclase mutants.