Cell Cycle-dependent Nuclear Localization of Yeast RNase III Is Required for Efficient Cell Division

Catala, Mathieu; Lamontagne, Bruno; Larose, Stéphanie; Ghazal, Ghada; Elela, Sherif Abou

doi:10.1091/mbc.e04-03-0183

Cited by 29 publications

(53 citation statements)

References 64 publications

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“…The localization pattern that we have described differs somewhat from the Rnt1p localization pattern described in two other studies (Huh et al 2003;Catala et al 2004). These studies show that Rnt1p localizes in the nucleus and the nucleolus, but they could not detect the dot-shaped territory that we describe.…”

Section: Analysis Of Rnt1p Localizationcontrasting

confidence: 79%

“…We show that Rnt1p import in the nucleus requires a nuclear localization signal found in the last 32 amino acids of the protein. The requirement of the C terminus of Rnt1p for nuclear import was also demonstrated in a recent study (Catala et al 2004). The C terminus of Rnt1p has similarities with classical importin ␣-type NLS, so it is reasonable to believe that import occurs through a classical importin ␣ pathway.…”

Section: Analysis Of Rnt1p Localizationsupporting

confidence: 63%

“…In the light of these considerations, we conclude that the observed nucleolar area in which Rnt1p is strongly accumulated corresponds to the site of transcription of the rDNA genes and early processing of the ribosomal RNA precursor. In support of this hypothesis, it was recently shown that the nucleolar accumulation of Rnt1p is reduced in a polymerase I temperature-sensitive strain (Catala et al 2004). However, analysis of Rnt1p localization in a rpa49⌬ strain, in which the levels of transcription by RNA polymerase I are reduced (Liljelund et al 1992), did not show a significant difference compared to wild-type cells (data not shown).…”

Section: A Cotranscriptional Model For Pre-rrna Processing At the 3 Ementioning

confidence: 79%

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A cotranscriptional model for 3′-end processing of the Saccharomyces cerevisiae pre-ribosomal RNA precursor

Henras¹,

Bertrand²,

Chanfreau³

2004

RNA

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Cleavage of the Saccharomyces cerevisiae primary ribosomal RNA (rRNA) transcript in the 3 external transcribed spacer (ETS) by Rnt1p generates the 35S pre-rRNA, the earliest detectable species in the pre-rRNA processing pathway. In this study we show that Rnt1p is concentrated in a subnucleolar dot-shaped territory distinct from the nucleolar body. The 35S pre-rRNA is localized at the periphery of the Rnt1p dot, in a pattern that suggests a diffusion of the 35S pre-rRNA from the site of Rnt1p processing. When plasmid-borne versions of the rDNA are used to express rRNAs, the Rnt1p territory reorganizes around these plasmids, suggesting a close association between Rnt1p and the plasmid-borne rDNA units. Rnt1p was found associated with the endogenous rDNA by chromatin immunoprecipitation. Deletion of functionally important Rnt1p domains result in a loss of the dot-shaped territory, showing that this subnucleolar territory corresponds to a functional site of processing. These results show that a large fraction of Rnt1p is localized at the site of transcription of the rDNA, suggesting that the cleavage of the primary pre-rRNA transcript to generate the 35S pre-rRNA is a cotranscriptional event.

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Section: Analysis Of Rnt1p Localizationcontrasting

confidence: 79%

Section: Analysis Of Rnt1p Localizationsupporting

confidence: 63%

Section: A Cotranscriptional Model For Pre-rrna Processing At the 3 Ementioning

confidence: 79%

See 1 more Smart Citation

A cotranscriptional model for 3′-end processing of the Saccharomyces cerevisiae pre-ribosomal RNA precursor

Henras¹,

Bertrand²,

Chanfreau³

2004

RNA

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“…Deletion of RNT1 impairs the processing and degradation of many snRNAs (1, 9), snoRNAs (24), and mRNAs (23, 39), causing major changes in cell metabolism (7). Moreover, the reduced growth rate of ⌬rnt1 cells may indirectly cause a general reduction in transcription (2).…”

Section: Rnapi Subunits Rpa12p and Rpa34p Interact Independently Withmentioning

confidence: 99%

Deletion of Rnt1p Alters the Proportion of Open versus Closed rRNA Gene Repeats in Yeast

Catala

Tremblay

Samson

et al. 2008

Molecular and Cellular Biology

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In Saccharomyces cerevisiae, the double-stranded-RNA-specific RNase III (Rnt1p) is required for the processing of pre-rRNA and coprecipitates with transcriptionally active rRNA gene repeats. Here we show that Rnt1p physically interacts with RNA polymerase I (RNAPI) and its deletion decreases the transcription of the rRNA gene and increases the number of rRNA genes with an open chromatin structure. In contrast, depletion of ribosomal proteins or factors that impair RNAPI termination did not increase the number of open rRNA gene repeats, suggesting that changes in the ratio of open and closed rRNA gene chromatin is not due to a nonspecific response to ribosome depletion or impaired termination. The results demonstrate that defects in pre-rRNA processing can influence the chromatin structure of the rRNA gene arrays and reveal links among the rRNA gene chromatin, transcription, and processing.In Saccharomyces cerevisiae, ribosomes are formed of 78 different ribosomal proteins assembled around four rRNAs. The synthesis of these essential protein factories involves three RNA polymerases and several processing factors (70). The ribosomal protein genes are transcribed by RNA polymerase II, while the rRNAs are transcribed by RNA polymerase I (RNAPI), with the exception of the 5S rRNA that is produced by RNA polymerase III. RNAPI produces the 18S, 5.8S, and 25S rRNAs as a single transcript containing two external transcribed spacers (ETS1 and -2) and two internal transcribed spacers (ITS1 and -2). Once transcribed, the rRNA precursor is processed to form the ribosome small subunit containing the 18S rRNA and the ribosome large subunit (LSU) containing the 5.8S and 25S rRNAs (69). RNAPI ( Fig. 1) is composed of five subunits common to all RNA polymerases, two subunits shared with RNA polymerase III, and seven unique subunits (53). All of the shared subunits are essential for yeast growth, as are the two largest unique subunits. The five remaining unique subunits are dispensable; however, the loss of Rpa12p causes temperature sensitivity and impairs RNAPI termination (21, 52). The last four RNAPIspecific subunits form two distinct complexes; one contains the Rpa34p and Rpa49p subunits, and the other contains the Rpa14p and Rpa43p subunits. The Rpa34p-Rpa49p complex is located near Rpa12p (Fig.

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“…Class I enzymes (in bacteria and bacteriophages) contain only one RNase domain (endoND) and a dsRNA-binding domain (dsRBD) (25). Class II riboendonucleases (in yeast) are highly variable and contain an additional 100-amino-acid N-terminal domain (10). Class III enzymes possess a dsRBD and two endoND domains.…”

mentioning

confidence: 99%

An Ascovirus-Encoded RNase III Autoregulates Its Expression and Suppresses RNA Interference-Mediated Gene Silencing

Hussain

Abraham

Asgari

2010

J Virol

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RNase III proteins play vital roles in processing of several types of RNA molecules and gene silencing. Recently, it has been discovered that some plant and animal viruses encode RNase III-like proteins as well. Genome sequencing of four virus species belonging to the Ascoviridae family has revealed sequence conservation of an RNase III open reading frame among the viruses. These have not been explored in ascoviruses, and therefore their role in host-virus interaction is unknown. Here, we confirmed expression of Heliothis virescens ascovirus (HvAV-3e) open reading frame 27 (orf27) that encodes an RNase III-like protein after infection and demonstrated dsRNA specific endoribonuclease activity of the encoded protein. Analysis of the expression patterns of orf27 in virus-infected insect cells and a bacterial expression system revealed autoregulation of this protein over time. Moreover, HvAV-3e RNase III was found essential for virus DNA replication and infection using RNA interference (RNAi)-mediated gene silencing. In addition, using green fluorescent protein gene as a marker, we provide evidence that RNase III is involved in the suppression of gene silencing. To our knowledge, this is the first insect virus-encoded RNase III described and shown to suppress host cell RNAi defense mechanism.

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Cell Cycle-dependent Nuclear Localization of Yeast RNase III Is Required for Efficient Cell Division

Cited by 29 publications

References 64 publications

A cotranscriptional model for 3′-end processing of the Saccharomyces cerevisiae pre-ribosomal RNA precursor

A cotranscriptional model for 3′-end processing of the Saccharomyces cerevisiae pre-ribosomal RNA precursor

Deletion of Rnt1p Alters the Proportion of Open versus Closed rRNA Gene Repeats in Yeast

An Ascovirus-Encoded RNase III Autoregulates Its Expression and Suppresses RNA Interference-Mediated Gene Silencing

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