Figure 3.

CCA1 and CCA2 are oppositely regulated during D. discoideum development. (A) Schematic presentation of the D. discoideum life cycle. Upon starvation, cells release cAMP as an external signal and move towards an aggregation center, where they form a multicellular organism. Eventually, this organism forms a fruiting body consisting of differentiated spore and stalk cells. Under improved growth conditions, the released spores grow out again into vegetative cells. (B) mRNA profiles of cca1 (DDB_G0293504) and cca2 (DDB_G0271378) genes according to dictyExpress. At time point 0, mRNA levels of cca1 are high and decrease during the first hours of development, increase again after 8 h and reach the initial level during the final stages of development. In contrast, mRNA levels of cca2 are close to zero at time point 0 and increase to a maximum after 4 to 8 h. Then, the levels decrease continuously until 24 h. Taken together, the diagram shows a diametrically contrary transcription of cca1 and cca2 genes, indicating specific functions during the life cycle.