Regeneration of cilia in Tetrahymena cells treated with 1 micrograms/ml of 4',6-diamidino-2-phenylindole (DAPI) takes place about 30 min later then in untreated controls. Analysis of RNA isolated at 50-th min of reciliation, that is when the control cells-but not DAPI-treated ones-have just restored their motility, revealed that; - 1. Two peaks of polyadenylated RNA were present in DAPI-treated cells as well as in the control ones; - 2. The mobility of the polyadenylated RNA was the same in the two compared cell samples; - 3. In wheat germ cell-free translational system these poly (A+)-RNA probably directed the synthesis of alpha- and beta-tubulin; - 4. The amount of polyadenylated RNA in compared cell samples was different, in DAPI-treated Tetrahymena its amount was estimated at 1.43% vs. 1.89% in control ones.