PRECISE EXPRESSION OF THE CAMP RECEPTOR GENE, CAR1, DURING TRANSITION FROM GROWTH TO DIFFERENTIATION IN DICTYOSTELIUM-DISCOIDEUM

The gene expressions associated with the switch-over from cell proliferation of Dictyostelium discoideum to differentiation have been analyzed using temperature shift and differential plaque hybridization methods. Quit1 was cloned as a specifically expressed gene when cells were starved just before the PS point (putative shift point from growth to differentiation). The coding region of the Quit1 gene is identical to that of the cAMP receptor 1 (CAR1) gene, which is essential for development. Quit1 mRNA was specifically expressed just after starvation of cells at around the PS point, thus indicating the importance of CAR1 for cellular differentiation as well as the actual existence of the PS point.