Localization of a new fiber-forming protein within Tetrahymena pyriformis.

As a step to study the biological function of a new protein, fiber-forming protein-38,000 (FFP-38), which was previously isolated from Tetrahymena pyriformis, its intracellular localization was investigated by using antiserum specific for FFP-38. Double immunodiffusion tests revealed that the anti-FFP-38 serum reacted with the protein(s) in isolated organelles such as oral apparatus, pellicles and mitochondria, to give rise to a precipitin line confluent with the line formed between the antiserum and the FFP-38. Furthermore, indirect fluorescent antibody staining showed that fluorescence was intensely localized in the oral apparatus and faintly distributed throughout the cytoplasm. In particular, distinct fluorescence was found along the division furrow of dividing Tetrahymena.