Direct measurement of tubulin and bulk message distributions on polysomes of growing, starved and deciliated Tetrahymena using RNA gel blots of sucrose gradients containing acrylamide. |
| |
Authors: | F J Calzone R Callahan M A Gorovsky |
| |
Affiliation: | Department of Biology, University of Rochester, NY 14627. |
| |
Abstract: | A method was developed using sucrose gradients containing acrylamide which greatly simplifies the measurement of the polysomal distribution of messages. After centrifugation, the acrylamide was polymerized, forming a polysome gel. RNA gel blots of polysome gels were used to determine the polysomal distributions of alpha-tubulin and total polyadenylated mRNA in growing, starved (nongrowing) and starved-deciliated Tetrahymena and the number of messages loaded onto polysomes was calculated. These measurements indicated that the translational efficiencies of alpha-tubulin mRNA and total polyadenylated mRNA are largely unaffected when the rates of tubulin and total protein synthesis vary dramatically. Thus, differential regulation of alpha-tubulin mRNA translation initiation does not contribute to the greater than 100-fold induction of tubulin synthesis observed during cilia regeneration and in growing cells. The major translation-level process regulating tubulin synthesis in Tetrahymena appears to be a change in message loading mediated by a non-specific message recruitment or unmasking factor. |
| |
Keywords: | |
|
|