Site of tubulin synthesis in Tetrahymena pyriformis

Abstract
Free and membrane‐bound polysomes were isolated from the protozoa Tetrahymena pyriformis, and the contribution of these two types of polysomes to tubulin synthesis were studied using immunoprecipitation of the 35S‐translational products in a rabbit reticulocyte lysate. One‐dimensional electrophoretic analysis shows that tubulin is synthesized by polyadenylated RNA isolated from free and membrane‐bound polysomes. Non‐polyadenylated RNAs of free polysomes are also able to direct tubulin synthesis. Two‐dimensional electrophoretic analysis using O'Farrell's system confirms these results and also reveals the existence of the α‐ and β‐tubulin subunits.