Protein synthesis patterns in conjugating Tetrahymena thermophila

Conjugation in Tetrahymena is a developmental system which results in a synchronized reorganization of the genetic material in both mates of a pair. Mass cultures of T. thermophila are easily induced to conjugate simultaneously, thus conjugation is amenable to cytological, genetical and biochemical studies. We investigated the changes in newly synthesized whole-cell proteins as a function of time after mixing of mating-competent cells, using [³⁵S]methionine pulse-labelling, one-dimensional polyacrylamide gel electrophoresis, and autoradiography. Concomitantly, the percentage of pairs and the cytological events were followed. Synthesis of at least ten protein bands with molecular weights larger than 50 kD are stimulated during the 5 h interval between mixing of the cells and meiosis of the gametic nuclei, whereas only minor protein synthesis takes place in the following 3 h. Two bands in particular are stimulated: one (81 kD, actD-insensitive) is synthesized until cells pair while the other (86 kD, actD-sensitive) is found between pairing and meiosis only.