scholarly journals Mild temperature shock alters the transcription of a discrete class of Saccharomyces cerevisiae genes.

1983 ◽  
Vol 3 (3) ◽  
pp. 457-465 ◽  
Author(s):  
C H Kim ◽  
J R Warner

In Saccharomyces cerevisiae the synthesis of ribosomal proteins declines temporarily after a culture has been subjected to a mild temperature shock, i.e., a shift from 23 to 36 degrees C, each of which support growth. Using cloned genes for several S. cerevisiae ribosomal proteins, we found that the changes in the synthesis of ribosomal proteins parallel the changes in the concentration of mRNA of each. The disappearance and reappearance of the mRNA is due to a brief but severe inhibition of the transcription of each of the ribosomal protein genes, although the total transcription of mRNA in the cells is relatively unaffected by the temperature shock. The precisely coordinated response of these genes, which are scattered throughout the genome, suggests that either they or the enzyme which transcribes them has unique properties. In certain S. cerevisiae mutants, the synthesis of ribosomal proteins never recovers from a temperature shift. Yet both the decline and the resumption of transcription of these genes during the 30 min after the temperature shift are indistinguishable from those in wild-type cells. The failure of the mutant cells to grow at the restrictive temperature appears to be due to their inability to process the RNA transcribed from genes which have introns (Rosbash et al., Cell 24:679-686, 1981), a large proportion of which appear to be ribosomal protein genes.

1983 ◽  
Vol 3 (3) ◽  
pp. 457-465
Author(s):  
C H Kim ◽  
J R Warner

In Saccharomyces cerevisiae the synthesis of ribosomal proteins declines temporarily after a culture has been subjected to a mild temperature shock, i.e., a shift from 23 to 36 degrees C, each of which support growth. Using cloned genes for several S. cerevisiae ribosomal proteins, we found that the changes in the synthesis of ribosomal proteins parallel the changes in the concentration of mRNA of each. The disappearance and reappearance of the mRNA is due to a brief but severe inhibition of the transcription of each of the ribosomal protein genes, although the total transcription of mRNA in the cells is relatively unaffected by the temperature shock. The precisely coordinated response of these genes, which are scattered throughout the genome, suggests that either they or the enzyme which transcribes them has unique properties. In certain S. cerevisiae mutants, the synthesis of ribosomal proteins never recovers from a temperature shift. Yet both the decline and the resumption of transcription of these genes during the 30 min after the temperature shift are indistinguishable from those in wild-type cells. The failure of the mutant cells to grow at the restrictive temperature appears to be due to their inability to process the RNA transcribed from genes which have introns (Rosbash et al., Cell 24:679-686, 1981), a large proportion of which appear to be ribosomal protein genes.


1982 ◽  
Vol 2 (10) ◽  
pp. 1199-1204 ◽  
Author(s):  
E Kraig ◽  
J E Haber ◽  
M Rosbash

In Saccharomyces cerevisiae, the levels of ribosomal protein mRNAs are regulated coordinately. Vegetative strains carrying the temperature-sensitive rna2 mutation exhibit a dramatic decrease in the levels of most ribosomal protein mRNAs at the restrictive temperature. Similarly, in wild-type cells induced to sporulate by nitrogen starvation, there is a fivefold reduction in the relative synthesis rate of ribosomal proteins. Using Northern gel analysis and cloned ribosomal protein genes, we compared the way in which ribosomal protein mRNA is affected under these two conditions. In vegetative rna2 cells, incubation at 34 degrees C led to the disappearance of ribosomal protein mRNAs and the accumulation of higher-molecular-weight precursor RNAs. A different phenotype was observed during sporulation. Although sporulating conditions led to a significant reduction in the relative abundance of ribosomal protein mRNA, there was no detectable accumulation of precursor RNAs even in rna2/rna2 diploids at 34 degrees C. A suppressor of rna2 and of other rna mutations, SRN1, at least partially relieved the block in the splicing of the ribosomal protein 51 intron in vegetative rna2 cells but did not detectably affect the level of ribosomal protein mRNA in sporulating cells. We concluded that the rna2 mutation and sporulation conditions affected ribosomal protein mRNA metabolism in two quite different ways. In vegetative cells the mutant rna2 effected a block which occurred primarily in post-transcriptional processing, whereas in sporulating cells the ribosomal protein mRNA levels were decreased by some other mechanism, presumably a change in the relative rate of transcription or mRNA turnover. Furthermore, the data suggest that the mutation rna2 has no additional effect on ribosomal protein mRNA metabolism in sporulating cells.


1982 ◽  
Vol 2 (10) ◽  
pp. 1199-1204
Author(s):  
E Kraig ◽  
J E Haber ◽  
M Rosbash

In Saccharomyces cerevisiae, the levels of ribosomal protein mRNAs are regulated coordinately. Vegetative strains carrying the temperature-sensitive rna2 mutation exhibit a dramatic decrease in the levels of most ribosomal protein mRNAs at the restrictive temperature. Similarly, in wild-type cells induced to sporulate by nitrogen starvation, there is a fivefold reduction in the relative synthesis rate of ribosomal proteins. Using Northern gel analysis and cloned ribosomal protein genes, we compared the way in which ribosomal protein mRNA is affected under these two conditions. In vegetative rna2 cells, incubation at 34 degrees C led to the disappearance of ribosomal protein mRNAs and the accumulation of higher-molecular-weight precursor RNAs. A different phenotype was observed during sporulation. Although sporulating conditions led to a significant reduction in the relative abundance of ribosomal protein mRNA, there was no detectable accumulation of precursor RNAs even in rna2/rna2 diploids at 34 degrees C. A suppressor of rna2 and of other rna mutations, SRN1, at least partially relieved the block in the splicing of the ribosomal protein 51 intron in vegetative rna2 cells but did not detectably affect the level of ribosomal protein mRNA in sporulating cells. We concluded that the rna2 mutation and sporulation conditions affected ribosomal protein mRNA metabolism in two quite different ways. In vegetative cells the mutant rna2 effected a block which occurred primarily in post-transcriptional processing, whereas in sporulating cells the ribosomal protein mRNA levels were decreased by some other mechanism, presumably a change in the relative rate of transcription or mRNA turnover. Furthermore, the data suggest that the mutation rna2 has no additional effect on ribosomal protein mRNA metabolism in sporulating cells.


1990 ◽  
Vol 10 (10) ◽  
pp. 5235-5243 ◽  
Author(s):  
D M Baronas-Lowell ◽  
J R Warner

In the yeast Saccharomyces cerevisiae, L30 is one of many ribosomal proteins that is encoded by two functional genes. We have cloned and sequenced RPL30B, which shows strong homology to RPL30A. Use of mRNA as a template for a polymerase chain reaction demonstrated that RPL30B contains an intron in its 5' untranslated region. This intron has an unusual 5' splice site, C/GUAUGU. The genomic copies of RPL30A and RPL30B were disrupted by homologous recombination. Growth rates, primer extension, and two-dimensional ribosomal protein analyses of these disruption mutants suggested that RPL30A is responsible for the majority of L30 production. Surprisingly, meiosis of a diploid strain carrying one disrupted RPL30A and one disrupted RPL30B yielded four viable spores. Ribosomes from haploid cells carrying both disrupted genes had no detectable L30, yet such cells grew with a doubling time only 30% longer than that of wild-type cells. Furthermore, depletion of L30 did not alter the ratio of 60S to 40S ribosomal subunits, suggesting that there is no serious effect on the assembly of 60S subunits. Polysome profiles, however, suggest that the absence of L30 leads to the formation of stalled translation initiation complexes.


1990 ◽  
Vol 10 (10) ◽  
pp. 5235-5243
Author(s):  
D M Baronas-Lowell ◽  
J R Warner

In the yeast Saccharomyces cerevisiae, L30 is one of many ribosomal proteins that is encoded by two functional genes. We have cloned and sequenced RPL30B, which shows strong homology to RPL30A. Use of mRNA as a template for a polymerase chain reaction demonstrated that RPL30B contains an intron in its 5' untranslated region. This intron has an unusual 5' splice site, C/GUAUGU. The genomic copies of RPL30A and RPL30B were disrupted by homologous recombination. Growth rates, primer extension, and two-dimensional ribosomal protein analyses of these disruption mutants suggested that RPL30A is responsible for the majority of L30 production. Surprisingly, meiosis of a diploid strain carrying one disrupted RPL30A and one disrupted RPL30B yielded four viable spores. Ribosomes from haploid cells carrying both disrupted genes had no detectable L30, yet such cells grew with a doubling time only 30% longer than that of wild-type cells. Furthermore, depletion of L30 did not alter the ratio of 60S to 40S ribosomal subunits, suggesting that there is no serious effect on the assembly of 60S subunits. Polysome profiles, however, suggest that the absence of L30 leads to the formation of stalled translation initiation complexes.


1989 ◽  
Vol 9 (3) ◽  
pp. 1191-1199
Author(s):  
M Bernstein ◽  
F Kepes ◽  
R Schekman

When incubated at a restrictive temperature, Saccharomyces cerevisiae sec59 mutant cells accumulate inactive and incompletely glycosylated forms of secretory proteins. Three different secretory polypeptides (invertase, pro-alpha-factor, and pro-carboxypeptidase Y) accumulated within a membrane-bounded organelle, presumably the endoplasmic reticulum, and resisted proteolytic degradation unless the membrane was permeabilized with detergent. Molecular cloning and DNA sequence analysis of the SEC59 gene predicted an extremely hydrophobic protein product of 59 kilodaltons. This prediction was confirmed by reconstitution of the sec59 defect in vitro. The alpha-factor precursor, which was translated in a soluble fraction from wild-type cells, was translocated into, but inefficiently glycosylated within, membranes from sec59 mutant cells. Residual glycosylation activity of membranes of sec59 cells was thermolabile compared with the activity of wild-type membranes. Partial restoration of glycosylation was obtained in reactions that were supplemented with mannose or GDP-mannose, but not those supplemented with other sugar nucleotides. These results were consistent with a role for the Sec59 protein in the transfer of mannose to dolichol-linked oligosaccharide.


1989 ◽  
Vol 9 (3) ◽  
pp. 1191-1199 ◽  
Author(s):  
M Bernstein ◽  
F Kepes ◽  
R Schekman

When incubated at a restrictive temperature, Saccharomyces cerevisiae sec59 mutant cells accumulate inactive and incompletely glycosylated forms of secretory proteins. Three different secretory polypeptides (invertase, pro-alpha-factor, and pro-carboxypeptidase Y) accumulated within a membrane-bounded organelle, presumably the endoplasmic reticulum, and resisted proteolytic degradation unless the membrane was permeabilized with detergent. Molecular cloning and DNA sequence analysis of the SEC59 gene predicted an extremely hydrophobic protein product of 59 kilodaltons. This prediction was confirmed by reconstitution of the sec59 defect in vitro. The alpha-factor precursor, which was translated in a soluble fraction from wild-type cells, was translocated into, but inefficiently glycosylated within, membranes from sec59 mutant cells. Residual glycosylation activity of membranes of sec59 cells was thermolabile compared with the activity of wild-type membranes. Partial restoration of glycosylation was obtained in reactions that were supplemented with mannose or GDP-mannose, but not those supplemented with other sugar nucleotides. These results were consistent with a role for the Sec59 protein in the transfer of mannose to dolichol-linked oligosaccharide.


1985 ◽  
Vol 5 (1) ◽  
pp. 99-108
Author(s):  
H M Fried ◽  
H G Nam ◽  
S Loechel ◽  
J Teem

We placed a regulatory sequence derived from the GAL10 locus of Saccharomyces cerevisiae at various distances from the start sites of transcription of two yeast ribosomal protein genes, tcm1 and cyh2. The hybrid ribosomal protein genes were transcribed at wild-type levels in the presence of galactose. In the absence of galactose, the hybrid genes were transcribed either at a reduced level or essentially not at all. Yeast cells which transcribe the ribosomal protein genes at a reduced rate continued to grow, suggesting that enhanced translation of the ribosomal protein mRNA may permit an adequate rate of synthesis of the corresponding protein. Consistent with this suggestion is the finding that preexisting mRNA decayed at a reduced rate when transcription was halted abruptly by removal of galactose. Yeast cells unable to transcribe tcm1 or cyh2 without galactose did not grow. These conditional lethal strains demonstrate that the ribosomal proteins encoded by tcm1 and cyh2 are essential; furthermore, these strains are potentially useful for isolating mutations in the tcm1 and cyh2 proteins affecting their transport, assembly, or function.


1981 ◽  
Vol 1 (11) ◽  
pp. 1016-1023 ◽  
Author(s):  
D R Kief ◽  
J R Warner

Saccharomyces cerevisiae cells respond to a heat shock by temporarily slowing the synthesis of ribosomal proteins (C. Gorenstein and J. R. Warner, Proc. Natl. Acad. Sci. U.S.A. 73:1574-1551, 1976). When cultures growing oxidatively on ethanol as the sole carbon source were shifted from 23 to 36 degrees C, the synthesis of ribosomal proteins was coordinately inhibited twice as rapidly and 45% more severely than in comparable cultures growing fermentatively on glucose. Within 15 min, the relative rates of synthesis of at least 30 ribosomal proteins declined to less than one-sixth their initial values, whereas the overall rate of protein synthesis increased at least threefold. We suggest that this is due primarily to controls at the level of synthesis of messenger ribonucleic acid for ribosomal proteins but may also involve changes in messenger ribonucleic acid stability. In contrast, a nutritional shift-up causes a stimulation of the synthesis of ribosomal proteins. Experiments designed to determine the hierarchy of stimuli affecting the synthesis of these proteins demonstrated that temperature shock was dominant to glucose stimulation. When a culture growing on ethanol was shifted from 23 to 36 degrees C and glucose was added shortly afterward, the decline in ribosomal protein synthesis continued unabated. However, in wild-type cells ribosomal protein synthesis began to recover within 15 min. In mutants temperature sensitive for ribosome synthesis, e.g., rna2, there was no recovery in the synthesis of most ribosomal proteins, suggesting that the product of rna2 is essential for the production of these proteins under all vegetative conditions.


Genetics ◽  
1996 ◽  
Vol 143 (2) ◽  
pp. 877-885 ◽  
Author(s):  
Stein Saeboe-Larssen ◽  
Andrew Lambertsson

Abstract Minutes comprise >50 phenotypically similar Drosophila mutations believed to affect ribosomal protein genes. Common traits of the Minute phenotype are short and thin bristles, slow development, and recessive lethality. To further investigate the proposed Minute to ribosomal protein correspondence, loss-of-function Minute mutations were induced by P-element mutagenesis. Here, we report a previously undescribed Minute locus that maps to 32A on chromosome 2L; this Minute allele is named P{lac-W}M(2)32A1 and the gene M(2)32A. Flies heterozygous for P{lacW}M(2)32A1 have a medium Minute phenotype. The gene interrupted by the P-element insertion was cloned. Sequence analyses revealed that it encodes the Drosophila homologue of eukaryotic ribosomal protein S13. It is a singlecopy gene and the level of RPS13 transcript is reduced to ~50% in P{lacW}M(2)32A1 heterozygotes. Both transcript level and phenotype are restored to wild type by remobilizing the P element, demonstrating that the mutation is caused by insertion of the P-element construct. These results further strengthen the notion that Minutes encode ribosomal proteins and demonstrate that P-element mutagenesis is a fruitful approach to use in these studies.


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