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Regulation of ribosome synthesis in <em>Tetrahymena pyriformis</em>. 3. Analysis by translation <em>in vitro</em> of RNA isolated during nutritional shift-down and nutritional shift-up.
- Source :
- European Journal of Biochemistry; 5/2/84, Vol. 140 Issue 3, p485-492, 8p
- Publication Year :
- 1984
-
Abstract
- We have measured the levels of translatable and mRNA and ribosomal protein (r-protein) mRNAs in Tetrahymena pyriformis during nutritional shifts. After 15 min of starvation total mRNA is reduced 2-fold, and after 24 h 7.5-fold, relative to exponentially growing cells. Upon refeeding total mRNA increases rapidly reaching the level of exponentially growing cells after 2.5 h. The levels of the individual r-protein mRNAs are coordinately regulated throughout a starvation-refeeding cycle. The relative levels of r-protein mRNAs remain virtually unchanged during the first hour of starvation and then decrease gradually to 30% of the relative levels in exponentially growing cells. Following refeeding the relative levels of r-protein mRNAs increase 6-fold. Taking into account the changes in whole cell RNA, we have calculated that long-time-starved Tetrahymena cells contain only 4% whereas cells after 3 h of refeeding contain 200% of the amount of r-protein mRNA in exponentially growing cells. The amount of r-protein mRNA thus increases 50-fold during the first 3 h of refeeding. A comparison between the relative levels of r-protein mRNAs and the relative rate of r-protein synthesis in vivo indicates that Tetrahymena employs a combination of control of translation and control of the level of r-protein mRNAs to ensure a rapid reduction in the rate of r-protein synthesis during the early period of starvation. In this period translation of r-protein mRNAs is preferentially inhibited. During refeeding the increase in the rate of r-protein synthesis parallels the increase in the abundance of r-protein mRNAs. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00142956
- Volume :
- 140
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- European Journal of Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 13824576
- Full Text :
- https://doi.org/10.1111/j.1432-1033.1984.tb08128.x