Induction of tubulin synthesis during cilia regeneration in growing Tetrahymena

Log growth Tetrahymena pyriformis GL were deciliated by means of a calcium pulse and allowed to regenerate their cilia in a non-nutrient recovery medium. Polyribosome profiles show only small amounts of polysomes up to 30 min after suspension in recovery medium. After this time the number of polysomes increases continuously as protein synthetic activity and motility are recovered. Labeling of whole cells with l-[³⁵S]methionine and comparison of the resulting electrophoretic patterns reveals a marked induction of tubulin synthesis as cilia regeneration proceeds. At its peak, tubulin accounts for 7–10% of the incorporated label but this peak occurs 35 min after the cells become greater than 90% motile and about 25 min after the cilia reach full length. These results are discussed with respect to the regulatory mechanism of tubulin induction and induction of tubulin synthesis in starved Tetrahymena.