Coupling of Transcription and Translation in <i>Dictyostelium discoideum </i>Nuclei

Mangiarotti, G

doi:10.1021/bi9822022

Cited by 19 publications

(9 citation statements)

References 27 publications

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“…Fresh evidence for nuclear translation has come from recent experiments with the slime mold Dictyostelium discoideum, in which polyribosome-like entities were identified in nuclei, based on their sedimentation in sucrose gradients, their ability to be pulse-labeled with [ 3 H]uracil, and their sensitivity to the protein synthesis inhibitor puromycin. (80) These putative nuclear polyribosomes cosedimented with both nascent mRNAs and nascent polypeptides. Based on this set of correlative data, it was concluded that transcription and translation are probably coupled in D. discoideum.…”

Section: Translation Factors Functioning In the Nucleus?mentioning

confidence: 99%

Multifunctional regulatory proteins that control gene expression in both the nucleus and the cytoplasm

Wilkinson

Shyu²

2001

BioEssays

106

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The multistep pathway of eukaryotic gene expression involves a series of highly regulated events in the nucleus and cytoplasm. In the nucleus, genes are transcribed into pre-messenger RNAs which undergo a series of nuclear processing steps. Mature mRNAs are then transported to the cytoplasm, where they are translated into protein and degraded at a rate dictated by transcript- and cell-type-specific cues. Until recently, these individual nuclear and cytoplasmic events were thought to be primarily regulated by different RNA- and DNA-binding proteins that are localized either only in the nucleus or only the cytoplasm. Here, we describe multifunctional proteins that control both nuclear and cytoplasmic steps of gene expression. One such class of multifunctional proteins (e.g., Bicoid and Y-box proteins) regulates both transcription and translation whereas another class (e.g., Sex-lethal) regulates both nuclear RNA processing and translation. Other events controlled by multifunctional proteins include assembly of spliceosome components, spliceosome recycling, RNA editing, cytoplasmic mRNA localization, and cytoplasmic RNA stability. The existence of multifunctional proteins may explain the paradoxical involvement of the nucleus in an RNA surveillance pathway (nonsense-mediated decay) that detects cytoplasmic signals (premature termination codons). We speculate that shuttling multifunctional proteins serve to efficiently link RNA metabolism in the cytoplasmic and nuclear compartments.

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Section: Translation Factors Functioning In the Nucleus?mentioning

confidence: 99%

Multifunctional regulatory proteins that control gene expression in both the nucleus and the cytoplasm

Wilkinson

Shyu²

2001

BioEssays

106

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“…However, it was shown more than two decades ago that a small fraction of amino acids are incorporated into polypeptides in the nucleus, but in those experiments a possible cytoplasmic contamination could not be excluded (Goidl and Ross 1978). More recently it was reported that in Dictyostelium discoideum nuclei nascent molecules of specific mR-NAs are associated with polyribosomes active in protein synthesis (Mangiarotti 1999). Because these results were obtained with isolated nuclei, it is difficult to exclude any cytoplasmic contamination.…”

Section: Introductionmentioning

confidence: 98%

Looking for nuclear translation using xenopus oocytes

Cosson

2003

Biology of the Cell

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In eukaryotes transcription and translation takes place in two different compartments separated by the nuclear envelope. Nuclear translation has been reported in several publications, however, all these published results have been criticized, particularly with respect to cytoplasmic contamination of the nuclei. We have investigated the question of nuclear protein synthesis using a different strategy. We microinjected frog oocytes with different DNA and RNA constructs and searched for translation products in nuclei separated from the cytoplasm by microdissection. We have been unable to detect any translation within the nuclei but rather a saturable translation in the perinuclear cytoplasm associated with the isolated nuclei.

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“…Mangiarotti (1999) provided evidence for the coupling of transcription and translation in Dictyostelium nuclei. Iborra et al (2001) reported that nascent polypeptides accumulate in the nucleus of HeLa cells, also concluding that transcription and translation are coupled.…”

Section: Introductionmentioning

confidence: 98%

Premature termination codons do not affect the rate of splicing of neighboring introns

Lytle

Steitz²

2004

RNA

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Introduction of a premature termination codon (PTC) into an exon of a gene can lead to nonsense-mediated decay of the mRNA, which is best characterized as a cytoplasmic event. However, increasing evidence has suggested that PTCs may also influence the nuclear processing of an RNA transcript, leading to models of nuclear surveillance perhaps involving translating nuclear ribosomes. We used quantitative RT-PCR to measure the in vivo steady-state levels of every exon-intron junction in wild-type, PTC-containing, and missense-containing precursor mRNAs of both the nonrearranging dihydrofolate reductase (DHFR) and the somatically rearranging Ig-µ genes. We find that each exon-intron junction's abundance and, therefore, the rate of intron removal, is not significantly affected by the presence of a PTC in a neighboring exon in either the DHFR or Ig-µ pre-mRNA. Similarly, the abundance of the uncleaved Ig-µ polyadenylation sites does not differ between wild-type and PTC-containing Ig-µ pre-mRNAs. Our Ig-µ data were confirmed by RNase protection analyses, and multiple cell isolates were examined to resolve differences with previously published data on steady-state pre-mRNA levels. We conclude that the presence of a PTC affects the rate of neither splicing nor the cleavage step of 3 end formation during pre-mRNA processing in the nucleus. Our results are discussed with respect to existing evidence for nuclear surveillance mechanisms.

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Coupling of Transcription and Translation in Dictyostelium discoideum Nuclei

Cited by 19 publications

References 27 publications

Multifunctional regulatory proteins that control gene expression in both the nucleus and the cytoplasm

Multifunctional regulatory proteins that control gene expression in both the nucleus and the cytoplasm

Looking for nuclear translation using xenopus oocytes

Premature termination codons do not affect the rate of splicing of neighboring introns

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