Статті в журналах: "SnR190"

1

Zagorski, J., D. Tollervey, and M. J. Fournier. "Characterization of an SNR gene locus in Saccharomyces cerevisiae that specifies both dispensible and essential small nuclear RNAs." Molecular and Cellular Biology 8, no. 8 (August 1988): 3282–90. http://dx.doi.org/10.1128/mcb.8.8.3282.

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A genetic locus is described that specifies two Saccharomyces cerevisiae small nuclear RNAs (snRNAs). The genes specifying the two snRNAs are separated by only 67 base pairs and are transcribed in the same direction. The product RNAs contain 128 and 190 nucleotides and are designated snR128 and snR190, respectively. These RNAs resemble snRNAs of other eucaryotes in nuclear localization and possession of a 5' trimethylguanosine cap. Neither snRNA is related in sequence to previously described vertebrate or yeast snRNAs. Both RNAs exhibit properties consistent with nucleolar organization and hydrogen bonding to pre-rRNA species, suggesting possible roles in ribosome biogenesis. The snR128 species cosediments with deproteinized 27S pre-rRNA, whereas snR190 is associated with a 20S intermediate. Gene disruption in vitro followed by replacement of the chromosomal alleles reveals that SNR128 is essential, whereas SNR190 is not.

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2

Zagorski, J., D. Tollervey, and M. J. Fournier. "Characterization of an SNR gene locus in Saccharomyces cerevisiae that specifies both dispensible and essential small nuclear RNAs." Molecular and Cellular Biology 8, no. 8 (August 1988): 3282–90. http://dx.doi.org/10.1128/mcb.8.8.3282-3290.1988.

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A genetic locus is described that specifies two Saccharomyces cerevisiae small nuclear RNAs (snRNAs). The genes specifying the two snRNAs are separated by only 67 base pairs and are transcribed in the same direction. The product RNAs contain 128 and 190 nucleotides and are designated snR128 and snR190, respectively. These RNAs resemble snRNAs of other eucaryotes in nuclear localization and possession of a 5' trimethylguanosine cap. Neither snRNA is related in sequence to previously described vertebrate or yeast snRNAs. Both RNAs exhibit properties consistent with nucleolar organization and hydrogen bonding to pre-rRNA species, suggesting possible roles in ribosome biogenesis. The snR128 species cosediments with deproteinized 27S pre-rRNA, whereas snR190 is associated with a 20S intermediate. Gene disruption in vitro followed by replacement of the chromosomal alleles reveals that SNR128 is essential, whereas SNR190 is not.

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3

Rasmussen, Theodore P., and Michael R. Culbertson. "The Putative Nucleic Acid Helicase Sen1p Is Required for Formation and Stability of Termini and for Maximal Rates of Synthesis and Levels of Accumulation of Small Nucleolar RNAs inSaccharomyces cerevisiae." Molecular and Cellular Biology 18, no. 12 (December 1, 1998): 6885–96. http://dx.doi.org/10.1128/mcb.18.12.6885.

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ABSTRACT Sen1p from Saccharomyces cerevisiae is a nucleic acid helicase related to DEAD box RNA helicases and type I DNA helicases. The temperature-sensitive sen1-1 mutation located in the helicase motif alters the accumulation of pre-tRNAs, pre-rRNAs, and some small nuclear RNAs. In this report, we show that cells carryingsen1-1 exhibit altered accumulation of several small nucleolar RNAs (snoRNAs) immediately upon temperature shift. Using Northern blotting, RNase H cleavage, primer extension, and base compositional analysis, we detected three forms of the snoRNA snR13 in wild-type cells: an abundant TMG-capped 124-nucleotide (nt) mature form (snR13F) and two less abundant RNAs, including a heterogeneous population of ∼1,400-nt 3′-extended forms (snR13R) and a 108-nt 5′-truncated form (snR13T) that is missing 16 nt at the 5′ end. A subpopulation of snR13R contains the same 5′ truncation. Newly synthesized snR13R RNA accumulates with time at the expense of snR13F following temperature shift of sen1-1 cells, suggesting a possible precursor-product relationship. snR13R and snR13T both increase in abundance at the restrictive temperature, indicating that Sen1p stabilizes the 5′ end and promotes maturation of the 3′ end. snR13F contains canonical C and D boxes common to many snoRNAs. The 5′ end of snR13T and the 3′ end of snR13F reside within C2U4 sequences that immediately flank the C and D boxes. A mutation in the 5′ C2U4 repeat causes underaccumulation of snR13F, whereas mutations in the 3′ C2U4 repeat cause the accumulation of two novel RNAs that migrate in the 500-nt range. At the restrictive temperature, double mutants carrying sen1-1 and mutations in the 3′ C2U4 repeat show reduced accumulation of the novel RNAs and increased accumulation of snR13R RNA, indicating that Sen1p and the 3′ C2U4 sequence act in a common pathway to facilitate 3′ end formation. Based on these findings, we propose that Sen1p and the C2U4 repeats that flank the C and D boxes promote maturation of the 3′ terminus and stability of the 5′ terminus and are required for maximal rates of synthesis and levels of accumulation of mature snR13F.

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4

Petfalski, Elisabeth, Thomas Dandekar, Yves Henry, and David Tollervey. "Processing of the Precursors to Small Nucleolar RNAs and rRNAs Requires Common Components." Molecular and Cellular Biology 18, no. 3 (March 1, 1998): 1181–89. http://dx.doi.org/10.1128/mcb.18.3.1181.

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ABSTRACT The genes encoding the small nucleolar RNA (snoRNA) species snR190 and U14 are located close together in the genome of Saccharomyces cerevisiae. Here we report that these two snoRNAs are synthesized by processing of a larger common transcript. In strains mutant for two 5′→3′ exonucleases, Xrn1p and Rat1p, families of 5′-extended forms of snR190 and U14 accumulate; these have 5′ extensions of up to 42 and 55 nucleotides, respectively. We conclude that the 5′ ends of both snR190 and U14 are generated by exonuclease digestion from upstream processing sites. In contrast to snR190 and U14, the snoRNAs U18 and U24 are excised from the introns of pre-mRNAs which encode proteins in their exonic sequences. Analysis of RNA extracted from a dbr1-Δ strain, which lacks intron lariat-debranching activity, shows that U24 can be synthesized only from the debranched lariat. In contrast, a substantial level of U18 can be synthesized in the absence of debranching activity. The 5′ ends of these snoRNAs are also generated by Xrn1p and Rat1p. The same exonucleases are responsible for the degradation of several excised fragments of the pre-rRNA spacer regions, in addition to generating the 5′ end of the 5.8S rRNA. Processing of the pre-rRNA and both intronic and polycistronic snoRNAs therefore involves common components.

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5

Marenda, Daniel R., Claudia B. Zraly, Yun Feng, Susan Egan, and Andrew K. Dingwall. "The Drosophila SNR1 (SNF5/INI1) Subunit Directs Essential Developmental Functions of the Brahma Chromatin Remodeling Complex." Molecular and Cellular Biology 23, no. 1 (January 1, 2003): 289–305. http://dx.doi.org/10.1128/mcb.23.1.289-305.2003.

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ABSTRACT The Drosophila melanogaster Brahma (Brm) complex, a counterpart of the Saccharomyces cerevisiae SWI/SNF ATP-dependent chromatin remodeling complex, is important for proper development by maintaining specific gene expression patterns. The SNR1 subunit is strongly conserved with yeast SNF5 and mammalian INI1 and is required for full activity of the Brm complex. We identified a temperature-sensitive allele of snr1 caused by a single amino acid substitution in the conserved repeat 2 region, implicated in a variety of protein-protein interactions. Genetic analyses of snr1E1 reveal that it functions as an antimorph and that snr1 has critical roles in tissue patterning and growth control. Temperature shifts show that snr1 is continuously required, with essential functions in embryogenesis, pupal stages, and adults. Allele-specific genetic interactions between snr1E1 and mutations in genes encoding other members of the Brm complex suggest that snr1E1 mutant phenotypes result from reduced Brm complex function. Consistent with this view, SNR1E1 is stably associated with other components of the Brm complex at the restrictive temperature. SNR1 can establish direct contacts through the conserved repeat 2 region with the SET domain of the homeotic regulator Trithorax (TRX), and SNR1E1 is partially defective for functional TRX association. As truncating mutations of INI1 are strongly correlated with aggressive cancers, our results support the view that SNR1, and specifically the repeat 2 region, has a critical role in mediating cell growth control functions of the metazoan SWI/SNF complexes.

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6

Clark, M. W., M. L. Yip, J. Campbell, and J. Abelson. "SSB-1 of the yeast Saccharomyces cerevisiae is a nucleolar-specific, silver-binding protein that is associated with the snR10 and snR11 small nuclear RNAs." Journal of Cell Biology 111, no. 5 (November 1, 1990): 1741–51. http://dx.doi.org/10.1083/jcb.111.5.1741.

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SSB-1, the yeast single-strand RNA-binding protein, is demonstrated to be a yeast nucleolar-specific, silver-binding protein. In double-label immunofluorescence microscopy experiments antibodies to two other nucleolar proteins, RNA Pol I 190-kD and fibrillarin, were used to reveal the site of rRNA transcription; i.e., the fibrillar region of the nucleolus. SSB-1 colocalized with fibrillarin in a double-label immunofluorescence mapping experiment to the yeast nucleolus. SSB-1 is located, though, over a wider region of the nucleolus than the transcription site marker. Immunoprecipitations of yeast cell extracts with the SSB-1 antibody reveal that in 150 mM NaCl SSB-1 is bound to two small nuclear RNAs (snRNAs). These yeast snRNAs are snR10 and snR11, with snR10 being predominant. Since snR10 has been implicated in pre-rRNA processing, the association of SSB-1 and snR10 into a nucleolar snRNP particle indicates SSB-1 involvement in rRNA processing as well. Also, another yeast protein, SSB-36-kD, isolated by single-strand DNA chromatography, is shown to bind silver under the conditions used for nucleolar-specific staining. It is, most likely, another yeast nucleolar protein.

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7

Morrissey, J. P., and D. Tollervey. "Yeast snR30 is a small nucleolar RNA required for 18S rRNA synthesis." Molecular and Cellular Biology 13, no. 4 (April 1993): 2469–77. http://dx.doi.org/10.1128/mcb.13.4.2469.

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Subnuclear fractionation and coprecipitation by antibodies against the nucleolar protein NOP1 demonstrate that the essential Saccharomyces cerevisiae RNA snR30 is localized to the nucleolus. By using aminomethyl trimethyl-psoralen, snR30 can be cross-linked in vivo to 35S pre-rRNA. To determine whether snR30 has a role in rRNA processing, a conditional allele was constructed by replacing the authentic SNR30 promoter with the GAL10 promoter. Repression of snR30 synthesis results in a rapid depletion of snR30 and a progressive increase in cell doubling time. rRNA processing is disrupted during the depletion of snR30; mature 18S rRNA and its 20S precursor underaccumulate, and an aberrant 23S pre-rRNA intermediate can be detected. Initial results indicate that this 23S pre-rRNA is the same as the species detected on depletion of the small nucleolar RNA-associated proteins NOP1 and GAR1 and in an snr10 mutant strain. It was found that the 3' end of 23S pre-rRNA is located in the 3' region of ITS1 between cleavage sites A2 and B1 and not, as previously suggested, at the B1 site, snR30 is the fourth small nucleolar RNA shown to play a role in rRNA processing.

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8

Morrissey, J. P., and D. Tollervey. "Yeast snR30 is a small nucleolar RNA required for 18S rRNA synthesis." Molecular and Cellular Biology 13, no. 4 (April 1993): 2469–77. http://dx.doi.org/10.1128/mcb.13.4.2469-2477.1993.

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Subnuclear fractionation and coprecipitation by antibodies against the nucleolar protein NOP1 demonstrate that the essential Saccharomyces cerevisiae RNA snR30 is localized to the nucleolus. By using aminomethyl trimethyl-psoralen, snR30 can be cross-linked in vivo to 35S pre-rRNA. To determine whether snR30 has a role in rRNA processing, a conditional allele was constructed by replacing the authentic SNR30 promoter with the GAL10 promoter. Repression of snR30 synthesis results in a rapid depletion of snR30 and a progressive increase in cell doubling time. rRNA processing is disrupted during the depletion of snR30; mature 18S rRNA and its 20S precursor underaccumulate, and an aberrant 23S pre-rRNA intermediate can be detected. Initial results indicate that this 23S pre-rRNA is the same as the species detected on depletion of the small nucleolar RNA-associated proteins NOP1 and GAR1 and in an snr10 mutant strain. It was found that the 3' end of 23S pre-rRNA is located in the 3' region of ITS1 between cleavage sites A2 and B1 and not, as previously suggested, at the B1 site, snR30 is the fourth small nucleolar RNA shown to play a role in rRNA processing.

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9

Ghazal, Ghada, Dongling Ge, Julien Gervais-Bird, Jules Gagnon, and Sherif Abou Elela. "Genome-Wide Prediction and Analysis of Yeast RNase III-Dependent snoRNA Processing Signals." Molecular and Cellular Biology 25, no. 8 (April 15, 2005): 2981–94. http://dx.doi.org/10.1128/mcb.25.8.2981-2994.2005.

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ABSTRACT In Saccharomyces cerevisiae, the maturation of both pre-rRNA and pre-small nucleolar RNAs (pre-snoRNAs) involves common factors, thereby providing a potential mechanism for the coregulation of snoRNA and rRNA synthesis. In this study, we examined the global impact of the double-stranded-RNA-specific RNase Rnt1p, which is required for pre-rRNA processing, on the maturation of all known snoRNAs. In silico searches for Rnt1p cleavage signals, and genome-wide analysis of the Rnt1p-dependent expression profile, identified seven new Rnt1p substrates. Interestingly, two of the newly identified Rnt1p-dependent snoRNAs, snR39 and snR59, are located in the introns of the ribosomal protein genes RPL7A and RPL7B. In vitro and in vivo experiments indicated that snR39 is normally processed from the lariat of RPL7A, suggesting that the expressions of RPL7A and snR39 are linked. In contrast, snR59 is produced by a direct cleavage of the RPL7B pre-mRNA, indicating that a single pre-mRNA transcript cannot be spliced to produce a mature RPL7B mRNA and processed by Rnt1p to produce a mature snR59 simultaneously. The results presented here reveal a new role of yeast RNase III in the processing of intron-encoded snoRNAs that permits independent regulation of the host mRNA and its associated snoRNA.

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10

Parker, R., T. Simmons, E. O. Shuster, P. G. Siliciano, and C. Guthrie. "Genetic analysis of small nuclear RNAs in Saccharomyces cerevisiae: viable sextuple mutant." Molecular and Cellular Biology 8, no. 8 (August 1988): 3150–59. http://dx.doi.org/10.1128/mcb.8.8.3150.

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Saccharomyces cerevisiae contains at least 24 distinct small nuclear RNAs (snRNAs), several of which are known to be essential for viability and to participate in the splicing of pre-mRNAs; the RNAs in this subset contain binding sites for the Sm antigen, a hallmark of metazoan snRNAs involved in mRNA processing. In contrast, we showed previously that the single-copy genes for three other snRNAs (snR3, snR4, and snR10) are not required for viability, although cells lacking snR10 are growth impaired at low temperature. None of these RNAs associates with the Sm antigen. To assess this apparent correlation, we cloned and sequenced the genes encoding three additional non-Sm snRNAs. Comparison of these genes with nine additional yeast snRNA genes revealed a highly conserved TATA box located 92 +/- 8 nucleotides 5' of the transcriptional start site. By using the technique of gene replacement with null alleles, each of these three single copy genes was shown to be completely dispensable. We constructed multiple mutants to test the hypothesis that, individually, each of these snRNAs is nonessential because the snRNAs play functionally overlapping roles. A mutant lacking five snRNAs (snR3, snR4, snR5, snR8, snR9) was indistinguishable from the wild type, and growth of the sextuple mutant was no more impaired than that in strains lacking only snR10. This widespread dispensability of snRNAs was completely unexpected and forces us to reconsider the possible roles of these ubiquitous RNAs.

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11

Parker, R., T. Simmons, E. O. Shuster, P. G. Siliciano, and C. Guthrie. "Genetic analysis of small nuclear RNAs in Saccharomyces cerevisiae: viable sextuple mutant." Molecular and Cellular Biology 8, no. 8 (August 1988): 3150–59. http://dx.doi.org/10.1128/mcb.8.8.3150-3159.1988.

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Saccharomyces cerevisiae contains at least 24 distinct small nuclear RNAs (snRNAs), several of which are known to be essential for viability and to participate in the splicing of pre-mRNAs; the RNAs in this subset contain binding sites for the Sm antigen, a hallmark of metazoan snRNAs involved in mRNA processing. In contrast, we showed previously that the single-copy genes for three other snRNAs (snR3, snR4, and snR10) are not required for viability, although cells lacking snR10 are growth impaired at low temperature. None of these RNAs associates with the Sm antigen. To assess this apparent correlation, we cloned and sequenced the genes encoding three additional non-Sm snRNAs. Comparison of these genes with nine additional yeast snRNA genes revealed a highly conserved TATA box located 92 +/- 8 nucleotides 5' of the transcriptional start site. By using the technique of gene replacement with null alleles, each of these three single copy genes was shown to be completely dispensable. We constructed multiple mutants to test the hypothesis that, individually, each of these snRNAs is nonessential because the snRNAs play functionally overlapping roles. A mutant lacking five snRNAs (snR3, snR4, snR5, snR8, snR9) was indistinguishable from the wild type, and growth of the sextuple mutant was no more impaired than that in strains lacking only snR10. This widespread dispensability of snRNAs was completely unexpected and forces us to reconsider the possible roles of these ubiquitous RNAs.

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12

Dandekar, Thomas. "Yeast U3 localization and correct sequence (snR17a) and promotor activity (snR17b) identified by homology search." DNA Sequence 1, no. 3 (January 1991): 217–18. http://dx.doi.org/10.3109/10425179109020774.

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13

Vos, Timothy John, and Ute Kothe. "snR30/U17 Small Nucleolar Ribonucleoprotein: A Critical Player during Ribosome Biogenesis." Cells 9, no. 10 (September 29, 2020): 2195. http://dx.doi.org/10.3390/cells9102195.

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The small nucleolar RNA snR30 (U17 in humans) plays a unique role during ribosome synthesis. Unlike most members of the H/ACA class of guide RNAs, the small nucleolar ribonucleoprotein (snoRNP) complex assembled on snR30 does not direct pseudouridylation of ribosomal RNA (rRNA), but instead snR30 is critical for 18S rRNA processing during formation of the small subunit (SSU) of the ribosome. Specifically, snR30 is essential for three pre-rRNA cleavages at the A0/01, A1/1, and A2/2a sites in yeast and humans, respectively. Accordingly, snR30 is the only essential H/ACA guide RNA in yeast. Here, we summarize our current knowledge about the interactions and functions of snR30, discuss what remains to be elucidated, and present two non-exclusive hypotheses on the possible molecular function of snR30 during ribosome biogenesis. First, snR30 might be responsible for recruiting other proteins including endonucleases to the SSU processome. Second, snR30 may contribute to the refolding of pre-rRNA into a required conformation that serves as a checkpoint during ribosome biogenesis facilitating pre-rRNA cleavage. In both scenarios, the snR30 snoRNP may have scaffolding and RNA chaperoning activity. In conclusion, the snR30 snoRNP is a crucial player with an unknown molecular mechanism during ribosome synthesis, posing many interesting future research questions.

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14

Li, Si-Guang, Hui Zhou, Yu-Ping Luo, Peng Zhang, and Liang-Hu Qu. "Identification and Functional Analysis of 20 Box H/ACA Small Nucleolar RNAs (snoRNAs) fromSchizosaccharomyces pombe." Journal of Biological Chemistry 280, no. 16 (February 16, 2005): 16446–55. http://dx.doi.org/10.1074/jbc.m500326200.

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Considering all small nucleolar RNAs (snoRNAs) enriched in the nucleolus, we generated a specialized cDNA library of small nuclear RNAs fromSchizosaccharomyces pombeand isolated, for the first time, 20 novel box H/ACA snoRNAs. Thirteen of these were characterized as novel guides that were predicted to direct 19 pseudouridylations in 18 S and 25 S rRNAs. The remaining seven snoRNAs were considered as orphan guides that lack sequence complementarity to either rRNAs or snRNAs. We have experimentally demonstrated the function of the 10 novel snoRNAs by gene deletion in the fission yeast. The snoRNAs were shown to be dispensable for the viability ofS. pombe, although an impact of snR94 depletion on yeast growth, especially at 23 °C, was revealed. A total of 30 pseudouridylation sites were precisely mapped in theS. pomberRNAs, showing a distinctive pseudouridylation pattern in the budding yeast. Interestingly, the absence of pseudouridylation on U2347 inS. pombe25 S rRNA pointed out a critical role for Ψ2345 in conferring a growth advantage for yeast. In contrast to the intron-encoded box C/D sno-RNAs in yeast, all box H/ACA snoRNAs appeared to be transcribed independently from intergenic regions between two protein-coding genes, except for snR35, which was nested in an open reading frame encoding for a hypothetical protein, although expressed from the opposite strand. Remarkably, snR90 was cotranscribed with an intron-encoded box C/D snoRNA, and this is the first demonstration of a non-coding RNA gene that encodes two different types of snoRNAs by its exon and intron. A detailed comparison of theS. pombesnoRNAs, with their functional homologues in diverse organisms, suggests a mechanism by which the snoRNAs have evolved in coordination with rRNAs to preserve the post-transcriptional modification sites among distant eukaryotes.

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15

Venema, J., C. Bousquet-Antonelli, J. P. Gelugne, M. Caizergues-Ferrer, and D. Tollervey. "Rok1p is a putative RNA helicase required for rRNA processing." Molecular and Cellular Biology 17, no. 6 (June 1997): 3398–407. http://dx.doi.org/10.1128/mcb.17.6.3398.

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The synthesis of ribosomes involves many small nucleolar ribonucleoprotein particles (snoRNPs) as transacting factors. Yeast strains lacking the snoRNA, snR10, are viable but are impaired in growth and delayed in the early pre-rRNA cleavages at sites A0, A1, and A2, which lead to the synthesis of 18S rRNA. The same cleavages are inhibited by genetic depletion of the essential snoRNP protein Gar1p. Screens for mutations showing synthetic lethality with deletion of the SNR10 gene or with a temperature-sensitive gar1 allele both identified the ROK1 gene, encoding a putative, ATP-dependent RNA helicase of the DEAD-box family. The ROK1 gene is essential for viability, and depletion of Rok1p inhibits pre-rRNA processing at sites A0, A1, and A2, thereby blocking 18S rRNA synthesis. Indirect immunofluorescence by using a ProtA-Rok1p construct shows the protein to be predominantly nucleolar. These results suggest that Rok1p is required for the function of the snoRNP complex carrying out the early pre-rRNA cleavage reactions.

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16

Atzorn, Vera, Paola Fragapane, and Tamás Kiss. "U17/snR30 Is a Ubiquitous snoRNA with Two Conserved Sequence Motifs Essential for 18S rRNA Production." Molecular and Cellular Biology 24, no. 4 (February 15, 2004): 1769–78. http://dx.doi.org/10.1128/mcb.24.4.1769-1778.2004.

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ABSTRACT Saccharomyces cerevisiae snR30 is an essential box H/ACA small nucleolar RNA (snoRNA) required for the processing of 18S rRNA. Here, we show that the previously characterized human, reptilian, amphibian, and fish U17 snoRNAs represent the vertebrate homologues of yeast snR30. We also demonstrate that U17/snR30 is present in the fission yeast Schizosaccharomyces pombe and the unicellular ciliated protozoan Tetrahymena thermophila. Evolutionary comparison revealed that the 3′-terminal hairpins of U17/snR30 snoRNAs contain two highly conserved sequence motifs, the m1 (AUAUUCCUA) and m2 (AAACCAU) elements. Mutation analysis of yeast snR30 demonstrated that the m1 and m2 elements are essential for early cleavages of the 35S pre-rRNA and, consequently, for the production of mature 18S rRNA. The m1 and m2 motifs occupy the opposite strands of an internal loop structure, and they are located invariantly 7 nucleotides upstream from the ACA box of U17/snR30 snoRNAs. U17/snR30 is the first identified box H/ACA snoRNA that possesses an evolutionarily conserved role in the nucleolytic processing of eukaryotic pre-rRNA.

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17

Adams, Elizabeth M., and Robert E. Moore. "Effects of Speech Rate, Background Noise, and Simulated Hearing Loss on Speech Rate Judgment and Speech Intelligibility in Young Listeners." Journal of the American Academy of Audiology 20, no. 01 (January 2009): 028–39. http://dx.doi.org/10.3766/jaaa.20.1.3.

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Purpose: To study the effect of noise on speech rate judgment and signal-to-noise ratio threshold (SNR50) at different speech rates (slow, preferred, and fast). Research Design: Speech rate judgment and SNR50 tasks were completed in a normal-hearing condition and a simulated hearing-loss condition. Study Sample: Twenty-four female and six male young, normal-hearing participants. Results: Speech rate judgment was not affected by background noise regardless of hearing condition. Results of the SNR50 task indicated that, as speech rate increased, performance decreased for both hearing conditions. There was a moderate correlation between speech rate judgment and SNR50 with the various speech rates, such that as judgment of speech rate increased from too slow to too fast, performance deteriorated. Conclusions: These findings can be used to support the need for counseling patients and their families about the potential advantages to using average speech rates or rates that are slightly slowed while conversing in the presence of background noise.

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18

Li, H. D., J. Zagorski, and M. J. Fournier. "Depletion of U14 small nuclear RNA (snR128) disrupts production of 18S rRNA in Saccharomyces cerevisiae." Molecular and Cellular Biology 10, no. 3 (March 1990): 1145–52. http://dx.doi.org/10.1128/mcb.10.3.1145.

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Repression of an essential nucleolar small nuclear RNA (snRNA) gene of Saccharomyces cerevisiae was shown to result in impaired production of 18S rRNA. The effect, observed for an snRNA species of 128 nucleotides (snR128), was evident within one generation after the onset of SNR128 gene repression and correlated well with depletion of the snRNA. The steady-state mass ratio of 18S RNA to 25S RNA decreased eightfold over the course of the analysis. Results from pulse-chase assays revealed the basis of the imbalance to be underaccumulation of 18S RNA and its 20S precursor. This effect appears to result from impairment of processing of the 35S rRNA transcript at sites that define the 20S species coupled with rapid turnover of unstable intermediates. Possible bases for the effects observed are discussed. A common U14 designation is proposed for the structurally related yeast snRNA and 4.5S hybRNAs from amphibians and mammals.

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19

Li, H. D., J. Zagorski, and M. J. Fournier. "Depletion of U14 small nuclear RNA (snR128) disrupts production of 18S rRNA in Saccharomyces cerevisiae." Molecular and Cellular Biology 10, no. 3 (March 1990): 1145–52. http://dx.doi.org/10.1128/mcb.10.3.1145-1152.1990.

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Repression of an essential nucleolar small nuclear RNA (snRNA) gene of Saccharomyces cerevisiae was shown to result in impaired production of 18S rRNA. The effect, observed for an snRNA species of 128 nucleotides (snR128), was evident within one generation after the onset of SNR128 gene repression and correlated well with depletion of the snRNA. The steady-state mass ratio of 18S RNA to 25S RNA decreased eightfold over the course of the analysis. Results from pulse-chase assays revealed the basis of the imbalance to be underaccumulation of 18S RNA and its 20S precursor. This effect appears to result from impairment of processing of the 35S rRNA transcript at sites that define the 20S species coupled with rapid turnover of unstable intermediates. Possible bases for the effects observed are discussed. A common U14 designation is proposed for the structurally related yeast snRNA and 4.5S hybRNAs from amphibians and mammals.

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20

Kinstrie, Ross, Pamela A. Lochhead, Gary Sibbet, Nick Morrice, and Vaughn Cleghon. "dDYRK2 and Minibrain interact with the chromatin remodelling factors SNR1 and TRX." Biochemical Journal 398, no. 1 (July 27, 2006): 45–54. http://dx.doi.org/10.1042/bj20060159.

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The DYRKs (dual specificity tyrosine phosphorylation-regulated kinases) are a conserved family of protein kinases that autophosphorylate a tyrosine residue in their activation loop by an intra-molecular mechanism and phosphorylate exogenous substrates on serine/threonine residues. Little is known about the identity of true substrates for DYRK family members and their binding partners. To address this question, we used full-length dDYRK2 (Drosophila DYRK2) as bait in a yeast two-hybrid screen of a Drosophila embryo cDNA library. Of 14 independent dDYRK2 interacting clones identified, three were derived from the chromatin remodelling factor, SNR1 (Snf5-related 1), and three from the essential chromatin component, TRX (trithorax). The association of dDYRK2 with SNR1 and TRX was confirmed by co-immunoprecipitation studies. Deletion analysis showed that the C-terminus of dDYRK2 modulated the interaction with SNR1 and TRX. DYRK family member MNB (Minibrain) was also found to co-precipitate with SNR1 and TRX, associations that did not require the C-terminus of the molecule. dDYRK2 and MNB were also found to phosphorylate SNR1 at Thr102in vitro and in vivo. This phosphorylation required the highly conserved DH-box (DYRK homology box) of dDYRK2, whereas the DH-box was not essential for phosphorylation by MNB. This is the first instance of phosphorylation of SNR1 or any of its homologues and implicates the DYRK family of kinases with a role in chromatin remodelling.

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21

Dingwall, A. K., S. J. Beek, C. M. McCallum, J. W. Tamkun, G. V. Kalpana, S. P. Goff, and M. P. Scott. "The Drosophila snr1 and brm proteins are related to yeast SWI/SNF proteins and are components of a large protein complex." Molecular Biology of the Cell 6, no. 7 (July 1995): 777–91. http://dx.doi.org/10.1091/mbc.6.7.777.

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During most of Drosophila development the regulation of homeotic gene transcription is controlled by two groups of regulatory genes, the trithorax group of activators and the Polycomb group of repressors. brahma (brm), a member of the trithorax group, encodes a protein related to the yeast SWI2/SNF2 protein, a subunit of a protein complex that assists sequence-specific activator proteins by alleviating the repressive effects of chromatin. To learn more about the molecular mechanisms underlying the regulation of homeotic gene transcription, we have investigated whether a similar complex exists in flies. We identified the Drosophila snr1 gene, a potential homologue of the yeast SNF5 gene that encodes a subunit of the yeast SWI/SNF complex. The snr1 gene is essential and genetically interacts with brm and trithorax (trx), suggesting cooperation in regulating homeotic gene transcription. The spatial and temporal patterns of expression of snr1 are similar to those of brm. The snr1 and brm proteins are present in a large (> 2 x 10(6) Da) complex, and they co-immunoprecipitate from Drosophila extracts. These findings provide direct evidence for conservation of the SWI/SNF complex in higher eucaryotes and suggest that the Drosophila brm/snr1 complex plays an important role in maintaining homeotic gene transcription during development by counteracting the repressive effects of chromatin.

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22

Bagni, Claudia, and Bruno Lapeyre. "Gar1p Binds to the Small Nucleolar RNAs snR10 and snR30in Vitrothrough a Nontypical RNA Binding Element." Journal of Biological Chemistry 273, no. 18 (May 1, 1998): 10868–73. http://dx.doi.org/10.1074/jbc.273.18.10868.

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23

Torchet, C., and S. Hermann-Le Denmat. "High dosage of the small nucleolar RNA snR10 specifically suppresses defects of a yeast rrp5 mutant." Molecular Genetics and Genomics 268, no. 1 (September 2002): 70–80. http://dx.doi.org/10.1007/s00438-002-0724-z.

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24

Steinmetz, Eric J., and David A. Brow. "Ssu72 Protein Mediates Both Poly(A)-Coupled and Poly(A)-Independent Termination of RNA Polymerase II Transcription." Molecular and Cellular Biology 23, no. 18 (September 15, 2003): 6339–49. http://dx.doi.org/10.1128/mcb.23.18.6339-6349.2003.

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ABSTRACT Termination of transcription by RNA polymerase II (Pol II) is a poorly understood yet essential step in eukaryotic gene expression. Termination of pre-mRNA synthesis is coupled to recognition of RNA signals that direct cleavage and polyadenylation of the nascent transcript. Termination of nonpolyadenylated transcripts made by Pol II in the yeast Saccharomyces cerevisiae, including the small nuclear and small nucleolar RNAs, requires distinct RNA elements recognized by the Nrd1 protein and other factors. We have used genetic selection to characterize the terminator of the SNR13 snoRNA gene, revealing a bipartite structure consisting of an upstream element closely matching a Nrd1-binding sequence and a downstream element similar to a cleavage/polyadenylation signal. Genome-wide selection for factors influencing recogniton of the SNR13 terminator yielded mutations in the gene coding for the essential Pol II-binding protein Ssu72. Ssu72 has recently been found to associate with the pre-mRNA cleavage/polyadenylation machinery, and we find that an ssu72 mutation that disrupts Nrd1-dependent termination also results in deficient poly(A)-dependent termination. These findings extend the parallels between the two termination pathways and suggest that they share a common mechanism to signal Pol II termination.

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25

Bally, Marc, John Hughes, and Gianni Cesareni. "SnR30: a new, essential small nuclear RNA fromSaccharomyces cerevisiae." Nucleic Acids Research 16, no. 12 (1988): 5291–303. http://dx.doi.org/10.1093/nar/16.12.5291.

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26

Liang, Sayuan, Tom Dresselaers, Karim Louchami, Ce Zhu, Yipeng Liu, and Uwe Himmelreich. "Comparison of different compressed sensing algorithms for low SNR19F MRI applications-Imaging of transplanted pancreatic islets and cells labeled with perfluorocarbons." NMR in Biomedicine 30, no. 11 (August 25, 2017): e3776. http://dx.doi.org/10.1002/nbm.3776.

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27

Zhou, Bo, and Guo-Zhong Jing. "Conformational Features of a Truncated Staphylococcal Nuclease R (SNR135) and Their Implications for Catalysis." Archives of Biochemistry and Biophysics 360, no. 1 (December 1998): 33–40. http://dx.doi.org/10.1006/abbi.1998.0919.

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28

Lemay, Vincent, Ahmed Hossain, Yvonne N. Osheim, Ann L. Beyer, and François Dragon. "Identification of novel proteins associated with yeast snR30 small nucleolar RNA." Nucleic Acids Research 39, no. 22 (September 5, 2011): 9659–70. http://dx.doi.org/10.1093/nar/gkr659.

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29

Torres-Campana, Daniela, Béatrice Horard, Sandrine Denaud, Gérard Benoit, Benjamin Loppin, and Guillermo A. Orsi. "Three classes of epigenomic regulators converge to hyperactivate the essential maternal gene deadhead within a heterochromatin mini-domain." PLOS Genetics 18, no. 1 (January 4, 2022): e1009615. http://dx.doi.org/10.1371/journal.pgen.1009615.

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The formation of a diploid zygote is a highly complex cellular process that is entirely controlled by maternal gene products stored in the egg cytoplasm. This highly specialized transcriptional program is tightly controlled at the chromatin level in the female germline. As an extreme case in point, the massive and specific ovarian expression of the essential thioredoxin Deadhead (DHD) is critically regulated in Drosophila by the histone demethylase Lid and its partner, the histone deacetylase complex Sin3A/Rpd3, via yet unknown mechanisms. Here, we identified Snr1 and Mod(mdg4) as essential for dhd expression and investigated how these epigenomic effectors act with Lid and Sin3A to hyperactivate dhd. Using Cut&Run chromatin profiling with a dedicated data analysis procedure, we found that dhd is intriguingly embedded in an H3K27me3/H3K9me3-enriched mini-domain flanked by DNA regulatory elements, including a dhd promoter-proximal element essential for its expression. Surprisingly, Lid, Sin3a, Snr1 and Mod(mdg4) impact H3K27me3 and this regulatory element in distinct manners. However, we show that these effectors activate dhd independently of H3K27me3/H3K9me3, and that dhd remains silent in the absence of these marks. Together, our study demonstrates an atypical and critical role for chromatin regulators Lid, Sin3A, Snr1 and Mod(mdg4) to trigger tissue-specific hyperactivation within a unique heterochromatin mini-domain.

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30

Bachellerie, Jean-Pierre. "U3 small nuclear RNA (snR17A RNA) and DFR1 genes are very closely linked in Saccharomyces cerevisiae." Gene 84, no. 1 (December 1989): 207–8. http://dx.doi.org/10.1016/0378-1119(89)90158-3.

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31

Hoareau-Aveilla, Coralie, Eléonore Fayet-Lebaron, Beáta E. Jády, Anthony K. Henras, and Tamás Kiss. "Utp23p is required for dissociation of snR30 small nucleolar RNP from preribosomal particles." Nucleic Acids Research 40, no. 8 (December 16, 2011): 3641–52. http://dx.doi.org/10.1093/nar/gkr1213.

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32

Lubben, B., P. Fabrizio, B. Kastner, and R. Luhrmann. "Isolation and characterization of the small nucleolar ribonucleoprotein particle snR30 from Saccharomyces cerevisiae." Journal of Biological Chemistry 270, no. 19 (May 1995): 11549–54. http://dx.doi.org/10.1074/jbc.270.19.11549.

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33

Vos, Timothy J., and Ute Kothe. "Synergistic interaction network between the snR30 RNP, Utp23, and ribosomal RNA during ribosome synthesis." RNA Biology 19, no. 1 (June 1, 2022): 764–73. http://dx.doi.org/10.1080/15476286.2022.2078092.

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34

Bohnsack, Markus T., Martin Kos, and David Tollervey. "Quantitative analysis of snoRNA association with pre‐ribosomes and release of snR30 by Rok1 helicase." EMBO reports 9, no. 12 (October 3, 2008): 1230–36. http://dx.doi.org/10.1038/embor.2008.184.

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35

Yamamoto, Miki L., Tyson A. Clark, Sherry L. Gee, Jeong-Ah Kang, Anthony C. Schweitzer, Amittha Wickrema, and John G. Conboy. "Alternative pre-mRNA splicing switches modulate gene expression in late erythropoiesis." Blood 113, no. 14 (April 2, 2009): 3363–70. http://dx.doi.org/10.1182/blood-2008-05-160325.

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Abstract Differentiating erythroid cells execute a unique gene expression program that insures synthesis of the appropriate proteome at each stage of maturation. Standard expression microarrays provide important insight into erythroid gene expression but cannot detect qualitative changes in transcript structure, mediated by RNA processing, that alter structure and function of encoded proteins. We analyzed stage-specific changes in the late erythroid transcriptome via use of high-resolution microarrays that detect altered expression of individual exons. Ten differentiation-associated changes in erythroblast splicing patterns were identified, including the previously known activation of protein 4.1R exon 16 splicing. Six new alternative splicing switches involving enhanced inclusion of internal cassette exons were discovered, as well as 3 changes in use of alternative first exons. All of these erythroid stage-specific splicing events represent activated inclusion of authentic annotated exons, suggesting they represent an active regulatory process rather than a general loss of splicing fidelity. The observation that 3 of the regulated transcripts encode RNA binding proteins (SNRP70, HNRPLL, MBNL2) may indicate significant changes in the RNA processing machinery of late erythroblasts. Together, these results support the existence of a regulated alternative pre-mRNA splicing program that is critical for late erythroid differentiation.

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36

Fayet-Lebaron, Eléonore, Vera Atzorn, Yves Henry, and Tamás Kiss. "18S rRNA processing requires base pairings of snR30 H/ACA snoRNA to eukaryote-specific 18S sequences." EMBO Journal 28, no. 9 (March 26, 2009): 1260–70. http://dx.doi.org/10.1038/emboj.2009.79.

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37

Lepreti, Fabio, Vincenzo Carbone, and Antonio Vecchio. "Scaling Properties and Persistence of Long-Term Solar Activity." Atmosphere 12, no. 6 (June 8, 2021): 733. http://dx.doi.org/10.3390/atmos12060733.

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The long-range correlations associated with the presence of persistence are investigated by applying the detrended fluctuation analysis (DFA) on three different proxies of long-term solar activity. The considered datasets are a sunspot number reconstruction (SNR04) obtained from the atmospheric activity of the cosmogenic isotope 14C derived from tree rings, a total solar irradiance reconstruction (TSIR12) obtained from several 10Be ice core records from Greenland and Antarctica in combination with the global record of 14C in tree rings and a new multi-proxy sunspot number reconstruction (SNR18), also derived from 10Be datasets and the global 14C production series. The DFA scaling exponents found for the three time series are similar (lying in the range between 0.70 and 0.77) and the scaling ranges are comparable. These results indicate the presence of long-range correlations with persistence, in substantial agreement with the findings of previous studies carried out on other solar activity indices and proxies.

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38

Sereti, Afroditi, Christos Sidiras, Nikos Eleftheriadis, Ioannis Nimatoudis, Gail D. Chermak, and Vasiliki Maria Iliadou. "On the Difference of Scoring in Speech in Babble Tests." Healthcare 10, no. 3 (February 28, 2022): 458. http://dx.doi.org/10.3390/healthcare10030458.

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Hearing is a complex ability that extends beyond the peripheral auditory system. A speech in noise/competition test is a valuable measure to include in the test battery when attempting to assess an individual’s “hearing”. The present study compared syllable vs. word scoring of the Greek Speech-in-Babble (SinB) test with 22 native Greek speaking children (6–12-year-olds) diagnosed with auditory processing disorder (APD) and 33 native Greek speaking typically developing children (6–12-year-olds). A three-factor analysis of variance revealed greater discriminative ability for syllable scoring than word scoring, with significant interactions between group and scoring. Two-way analysis of variance revealed SinB word-based measures (SNR50%) were larger (poorer performance) than syllable-based measures for both groups of children. Cohen’s d values were larger for syllable-based mean scores compared to word-based mean scores between groups for both ears. These findings indicate that the type of scoring affects the SinB’s resolution capacity and that syllable scoring might better differentiate typically developing children and children with APD.

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39

Liang, Xue-hai, and Maurille J. Fournier. "The Helicase Has1p Is Required for snoRNA Release from Pre-rRNA." Molecular and Cellular Biology 26, no. 20 (August 14, 2006): 7437–50. http://dx.doi.org/10.1128/mcb.00664-06.

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ABSTRACT Synthesis of rRNA in eukaryotes involves the action of a large population of snoRNA-protein complexes (snoRNPs), which create modified nucleotides and participate in cleavage of pre-rRNA. The snoRNPs mediate these functions through direct base pairing, in many cases through long complementary sequences. This feature suggests that RNA helicases may be involved in the binding and release of snoRNPs from pre-rRNA. In this study, we determined that the DEAD box helicase Has1p, a nucleolar protein required for the production of 18S rRNA, copurifies with the snR30/U17 processing snoRNP but is also present with other snoRNPs. Blocking Has1p expression causes a substantial increase in snoRNPs associated with 60S-90S preribosomal RNP complexes, including the U3 and U14 processing snoRNPs and several modifying snoRNPs examined. Cosedimentation persisted even after deproteinization. This effect was not observed with depletion of two nonhelicase proteins, Esf1p and Dim2p, that are also required for 18S rRNA production. Point mutations in ATPase and helicase motifs of Has1p block U14 release from pre-rRNA. Surprisingly, depletion of Has1p causes a reduction in the level of free U6 snRNP. The results indicate that the Has1p helicase is required for snoRNA release from pre-rRNA and production of the U6 snRNP.

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40

Balarezo-Cisneros, Laura Natalia, Steven Parker, Marcin G. Fraczek, Soukaina Timouma, Ping Wang, Raymond T. O’Keefe, Catherine B. Millar, and Daniela Delneri. "Functional and transcriptional profiling of non-coding RNAs in yeast reveal context-dependent phenotypes and in trans effects on the protein regulatory network." PLOS Genetics 17, no. 1 (January 25, 2021): e1008761. http://dx.doi.org/10.1371/journal.pgen.1008761.

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Non-coding RNAs (ncRNAs), including the more recently identified Stable Unannotated Transcripts (SUTs) and Cryptic Unstable Transcripts (CUTs), are increasingly being shown to play pivotal roles in the transcriptional and post-transcriptional regulation of genes in eukaryotes. Here, we carried out a large-scale screening of ncRNAs in Saccharomyces cerevisiae, and provide evidence for SUT and CUT function. Phenotypic data on 372 ncRNA deletion strains in 23 different growth conditions were collected, identifying ncRNAs responsible for significant cellular fitness changes. Transcriptome profiles were assembled for 18 haploid ncRNA deletion mutants and 2 essential ncRNA heterozygous deletants. Guided by the resulting RNA-seq data we analysed the genome-wide dysregulation of protein coding genes and non-coding transcripts. Novel functional ncRNAs, SUT125, SUT126, SUT035 and SUT532 that act in trans by modulating transcription factors were identified. Furthermore, we described the impact of SUTs and CUTs in modulating coding gene expression in response to different environmental conditions, regulating important biological process such as respiration (SUT125, SUT126, SUT035, SUT432), steroid biosynthesis (CUT494, SUT053, SUT468) or rRNA processing (SUT075 and snR30). Overall, these data capture and integrate the regulatory and phenotypic network of ncRNAs and protein-coding genes, providing genome-wide evidence of the impact of ncRNAs on cellular homeostasis.

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41

Xie, Gengqiang, Hanqing Chen, Dongyu Jia, Zhiqiang Shu, William Hunt Palmer, Yi-Chun Huang, Xiankun Zeng, Steven X. Hou, Renjie Jiao, and Wu-Min Deng. "The SWI/SNF Complex Protein Snr1 Is a Tumor Suppressor in Drosophila Imaginal Tissues." Cancer Research 77, no. 4 (December 6, 2016): 862–73. http://dx.doi.org/10.1158/0008-5472.can-16-0963.

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42

Carroll, Kristina L., Dennis A. Pradhan, Josh A. Granek, Neil D. Clarke, and Jeffry L. Corden. "Identification of cis Elements Directing Termination of Yeast Nonpolyadenylated snoRNA Transcripts." Molecular and Cellular Biology 24, no. 14 (July 15, 2004): 6241–52. http://dx.doi.org/10.1128/mcb.24.14.6241-6252.2004.

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ABSTRACT RNA polymerase II (Pol II) termination is triggered by sequences present in the nascent transcript. Termination of pre-mRNA transcription is coupled to recognition of cis-acting sequences that direct cleavage and polyadenylation of the pre-mRNA. Termination of nonpolyadenylated [non-poly(A)] Pol II transcripts in Saccharomyces cerevisiae requires the RNA-binding proteins Nrd1 and Nab3. We have used a mutational strategy to characterize non-poly(A) termination elements downstream of the SNR13 and SNR47 snoRNA genes. This approach detected two common RNA sequence motifs, GUA[AG] and UCUU. The first motif corresponds to the known Nrd1-binding site, which we have verified here by gel mobility shift assays. We also show that Nab3 protein binds specifically to RNA containing the UCUU motif. Taken together, our data suggest that Nrd1 and Nab3 binding sites play a significant role in defining non-poly(A) terminators. As is the case with poly(A) terminators, there is no strong consensus for non-poly(A) terminators, and the arrangement of Nrd1p and Nab3p binding sites varies considerably. In addition, the organization of these sequences is not strongly conserved among even closely related yeasts. This indicates a large degree of genetic variability. Despite this variability, we were able to use a computational model to show that the binding sites for Nrd1 and Nab3 can identify genes for which transcription termination is mediated by these proteins.

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43

Taoka, Masato, Yuko Nobe, Yuka Yamaki, Yoshio Yamauchi, Hideaki Ishikawa, Nobuhiro Takahashi, Hiroshi Nakayama, and Toshiaki Isobe. "The complete chemical structure ofSaccharomyces cerevisiaerRNA: partial pseudouridylation of U2345 in 25S rRNA by snoRNA snR9." Nucleic Acids Research 44, no. 18 (June 20, 2016): 8951–61. http://dx.doi.org/10.1093/nar/gkw564.

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44

静, 国忠, 柱礼万, 波. 周, 栋材梁 та 升. 叶. "葡萄球菌核酸酶R型N端片段:SNR141的晶体生长及初步晶体学分析". Chinese Science Bulletin 42, № 9 (1 травня 1997): 983–85. http://dx.doi.org/10.1360/csb1997-42-9-983.

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45

Santangelo, George M., Joanne Tornow, Calvin S. McLaughlin, and Kivie Moldave. "Screening a yeast promoter library leads to the isolation of the RP29/L32 and SNR17B/RPL37A divergent promoters and the discovery of a gene encoding ribosomal protein L37." Gene 105, no. 1 (August 1991): 137–38. http://dx.doi.org/10.1016/0378-1119(91)90526-h.

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46

Gerbi, Susan A. "Small nucleolar RNA." Biochemistry and Cell Biology 73, no. 11-12 (December 1, 1995): 845–58. http://dx.doi.org/10.1139/o95-092.

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A growing list of small nucleolar RNAs (snoRNAs) has been characterized in eukaryotes. They are transcribed by RNA polymerase II or III; some snoRNAs are encoded in the introns of other genes. The nonintronic polymerase II transcribed snoRNAs receive a trimethylguanosine cap, probably in the nucleus, and move to the nucleolus. snoRNAs are complexed with proteins, sometimes including fibrillarin. Localization and maintenance in the nucleolus of some snoRNAs requires the presence of initial precursor rRNA (pre-rRNA). Many snoRNAs have conserved sequence boxes C and D and a 3′ terminal stem; the roles of these features are discussed. Functional assays done for a few snoRNAs indicate their roles in rRNA processing for cleavage of the external and internal transcribed spacers (ETS and ITS). U3 is the most abundant snoRNA and is needed for cleavage of ETS1 and ITS1; experimental results on U3 binding sites in pre-rRNA are reviewed. 18S rRNA production also needs U14, U22, and snR30 snoRNAs, whereas U8 snoRNA is needed for 5.8S and 28S rRNA production. Other snoRNAs that are complementary to 18S or 28S rRNA might act as chaperones to mediate RNA folding. Whether snoRNAs join together in a large rRNA processing complex (the "processome") is not yet clear. It has been hypothesized that such complexes could anchor the ends of loops in pre-rRNA containing 18S or 28S rRNA, thereby replacing base-paired stems found in pre-rRNA of prokaryotes.Key words: RNA processing, small nucleolar RNAs, nucleolus, ribosome biogenesis, rRNA processing complex.

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47

Zraly, Claudia B., Daniel R. Marenda, and Andrew K. Dingwall. "SNR1 (INI1/SNF5) Mediates Important Cell Growth Functions of the Drosophila Brahma (SWI/SNF) Chromatin Remodeling Complex." Genetics 168, no. 1 (September 2004): 199–214. http://dx.doi.org/10.1534/genetics.104.029439.

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48

Zraly, Claudia B., Daniel R. Marenda, Runjhun Nanchal, Giacomo Cavalli, Christian Muchardt, and Andrew K. Dingwall. "SNR1 is an essential subunit in a subset of drosophila brm complexes, targeting specific functions during development." Developmental Biology 253, no. 2 (January 2003): 291–308. http://dx.doi.org/10.1016/s0012-1606(02)00011-8.

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49

Degrand, Chantal, and Rita Prest. "Direct electrochemical synthesis of symmetrical aromatic diselenides and ditellurides by SNR1 substitution using Se and Te electrodes." Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 282, no. 1-2 (October 1990): 281–86. http://dx.doi.org/10.1016/0022-0728(91)85105-x.

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50

Němcová, Andrea, Radovan Smíšek, Lucie Maršánová, Lukáš Smital, and Martin Vítek. "A Comparative Analysis of Methods for Evaluation of ECG Signal Quality after Compression." BioMed Research International 2018 (July 18, 2018): 1–26. http://dx.doi.org/10.1155/2018/1868519.

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The assessment of ECG signal quality after compression is an essential part of the compression process. Compression facilitates the signal archiving, speeds up signal transmission, and reduces the energy consumption. Conversely, lossy compression distorts the signals. Therefore, it is necessary to express the compression performance through both compression efficiency and signal quality. This paper provides an overview of objective algorithms for the assessment of both ECG signal quality after compression and compression efficiency. In this area, there is a lack of standardization, and there is no extensive review as such. 40 methods were tested in terms of their suitability for quality assessment. For this purpose, the whole CSE database was used. The tested signals were compressed using an algorithm based on SPIHT with varying efficiency. As a reference, compressed signals were manually assessed by two experts and classified into three quality groups. Owing to the experts’ classification, we determined corresponding ranges of selected quality evaluation methods’ values. The suitability of the methods for quality assessment was evaluated based on five criteria. For the assessment of ECG signal quality after compression, we recommend using a combination of these methods: PSim SDNN, QS, SNR1, MSE, PRDN1, MAX, STDERR, and WEDD SWT.

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