Nucleic Acids Research, 1988, Vol. 16, No. 20 9597-9609
© 1988
Articles |
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
Department of Biology, University of Rochester Rochester, NY 14627, USA
Received July 7, 1988. Accepted September 22, 1988.
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 a-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 a-tubulin mRNA and total polyadenylated mRNA are largely unaffected when the rates of tubulin and total protein synthesis vary dramatically. Thus, differential regulation of a-tubulin mRNA translation initiation does not contribute to the >100-fold induction of tubulin synthesis observed during cilia regeneration and in growing cells. The major translation-level process regulating tubulin synthesis inTetrahymena appears to be a change in message loading mediated by a non-specific message recruitment or unmasking factor.
+Present address: Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA