Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID:Sporulation and rna2 lower ribosomal protein mRNA levels by different mechanisms in Saccharomyces cerevisiae. 675 16

Yeast ribosomal protein genes are coordinately regulated as a function of cell growth; RNA levels decrease during amino acid starvation but increase following a carbon source upshift. Binding sites for RAP1, a multifunctional transcription factor, are present in nearly all ribosomal protein genes and are associated with growth rate regulation. We show that ribosomal protein mRNA levels are increased twofold in strains that have constitutively high levels of cyclic AMP-dependent protein kinase (protein kinase A [PKA]) activity. The PKA-dependent induction requires RAP1 binding sites, and it reflects increased transcriptional activation by RAP1. Growth-regulated transcription of ribosomal protein genes strongly depends on the ability to regulate PKA activity. Cells with constitutively high PKA levels do not show the transcriptional decrease in response to amino acid starvation. Conversely, in cells with constitutively low PKA activity, ribosomal protein mRNAs levels are lower and largely uninducible upon carbon source upshift. We suggest that modulation of RAP1 transcriptional activity by PKA accounts for growth-regulated expression of ribosomal protein genes.
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PMID:Protein kinase A mediates growth-regulated expression of yeast ribosomal protein genes by modulating RAP1 transcriptional activity. 811 23

We have performed a detailed quantitative analysis of the transcription and accumulation of ribosomal RNA and ribosomal protein mRNA in the ciliated protozoan Tetrahymena thermophila during changes in growth conditions, and found that: (1) nutritional downshifts lead to a rapid decrease in transcriptional activity whereas nutritional upshifts lead to rapid restoration of transcriptional activity, (2) starvation leads to decreased translation of ribosomal protein mRNA and (3) the rate of ribosomal protein mRNA degradation decreases after a nutritional upshift. We present evidence that the proximal promoters of two ribosomal protein genes and the ribosomal RNA gene compete for binding of nuclear factor(s) in vitro, suggesting that the coordinated regulation of these genes may involve a common set of transcriptional regulators.
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PMID:Ribosome synthesis in Tetrahymena: a quantitative analysis. 1073 97

MicroRNAs (miRNAs) are small RNAs that function as posttranscriptional regulators of gene expression. miRNAs affect a variety of signaling pathways, and impaired miRNA regulation may contribute to the development of cancer and other diseases. Here we show that miRNA miR-10a interacts with the 5' untranslated region of mRNAs encoding ribosomal proteins to enhance their translation. miR-10a alleviates translational repression of the ribosomal protein mRNAs during amino acid starvation and is required for their translational induction following anisomycin treatment or overexpression of RAS. We show that miR-10a binds immediately downstream of the regulatory 5'TOP motif and that the 5'TOP regulatory complex and miR-10a are functionally interconnected. The results show that miR-10a may positively control global protein synthesis via the stimulation of ribosomal protein mRNA translation and ribosome biogenesis and hereby affect the ability of cells to undergo transformation.
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PMID:MicroRNA-10a binds the 5'UTR of ribosomal protein mRNAs and enhances their translation. 1849 49