scholarly journals The rRNA enhancer regulates rRNA transcription in Saccharomyces cerevisiae.

1993 ◽  
Vol 13 (2) ◽  
pp. 1283-1289 ◽  
Author(s):  
B E Morrow ◽  
S P Johnson ◽  
J R Warner
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Binding Sites ◽  
Major Element ◽  
Transcription Unit ◽  
Rrna Genes ◽  
Nutritional Regulation ◽  
Rrna Transcription ◽  
Enhancer Function

In Saccharomyces cerevisiae, the rRNA genes are organized as a tandem array of head-to-tail repeats. An enhancer of rRNA transcription is present just at the end of each transcription unit, 2 kb away from the next one. This enhancer is unusual for S. cerevisiae in that it acts both upstream and downstream of, and even across, genes. The role of the enhancer in the nutritional regulation of rRNA transcription was studied by introducing a centromere plasmid carrying two rRNA minigenes in tandem, flanking a single enhancer, into cells. Analysis of the transcripts from the two minigenes showed that the enhancer was absolutely required for the stimulation of transcription of rRNA that occurs when cells are shifted from a poor carbon source to a good carbon source. While full enhancer function is provided by a 45-bp region at the 3' end of the 190-bp enhancer, some activity was also conferred by other elements, including both a T-rich stretch and a region containing the binding sites for the proteins Reb1p and Abf1p. We conclude that the enhancer is composed of redundant elements and that it is a major element in the regulation of rRNA transcription.

The rRNA enhancer regulates rRNA transcription in Saccharomyces cerevisiae

1993 ◽  
Vol 13 (2) ◽  
pp. 1283-1289
Author(s):  
B E Morrow ◽  
S P Johnson ◽  
J R Warner
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Binding Sites ◽  
Major Element ◽  
Transcription Unit ◽  
Rrna Genes ◽  
Nutritional Regulation ◽  
Rrna Transcription ◽  
Enhancer Function

In Saccharomyces cerevisiae, the rRNA genes are organized as a tandem array of head-to-tail repeats. An enhancer of rRNA transcription is present just at the end of each transcription unit, 2 kb away from the next one. This enhancer is unusual for S. cerevisiae in that it acts both upstream and downstream of, and even across, genes. The role of the enhancer in the nutritional regulation of rRNA transcription was studied by introducing a centromere plasmid carrying two rRNA minigenes in tandem, flanking a single enhancer, into cells. Analysis of the transcripts from the two minigenes showed that the enhancer was absolutely required for the stimulation of transcription of rRNA that occurs when cells are shifted from a poor carbon source to a good carbon source. While full enhancer function is provided by a 45-bp region at the 3' end of the 190-bp enhancer, some activity was also conferred by other elements, including both a T-rich stretch and a region containing the binding sites for the proteins Reb1p and Abf1p. We conclude that the enhancer is composed of redundant elements and that it is a major element in the regulation of rRNA transcription.

Unusual enhancer function in yeast rRNA transcription

1989 ◽  
Vol 9 (11) ◽  
pp. 4986-4993
Author(s):  
S P Johnson ◽  
J R Warner
Keyword(s):  
Transcription Initiation ◽  
Initiation Site ◽  
Transcription Unit ◽  
Rrna Genes ◽  
Yeast Saccharomyces Cerevisiae ◽  
Rrna Transcription ◽  
Enhancer Function ◽  
Polymerase I ◽  
Relationship Of ◽  
The Relationship

The rRNA genes in most eucaryotic organisms are present in a tandem array. There is substantial evidence that transcription of one of these genes may not be independent of transcription of others. In particular, in the yeast Saccharomyces cerevisiae, the enhancer of rRNA transcription that lies 2.2 kilobases 5' of the transcription initiation site is at least partly within the upstream transcription unit. To ask more directly about the relationship of the tandemness of these genes to their transcription, we have constructed a minirepeat containing two identifiable test genes, with or without enhancer(s). On integration into the URA3 locus, these genes were transcribed by RNA polymerase I. A single enhancer effectively stimulated transcription of both genes by 10- to 30-fold, even when it was located upstream of both or downstream of both. Two enhancers had roughly additive effects. These results suggest a model of enhancer function in tandemly repeated genes.

scholarly journals Unusual enhancer function in yeast rRNA transcription.

1989 ◽  
Vol 9 (11) ◽  
pp. 4986-4993 ◽  
Author(s):  
S P Johnson ◽  
J R Warner
Keyword(s):  
Transcription Initiation ◽  
Initiation Site ◽  
Transcription Unit ◽  
Rrna Genes ◽  
Yeast Saccharomyces Cerevisiae ◽  
Rrna Transcription ◽  
Enhancer Function ◽  
Polymerase I ◽  
Relationship Of ◽  
The Relationship

The rRNA genes in most eucaryotic organisms are present in a tandem array. There is substantial evidence that transcription of one of these genes may not be independent of transcription of others. In particular, in the yeast Saccharomyces cerevisiae, the enhancer of rRNA transcription that lies 2.2 kilobases 5' of the transcription initiation site is at least partly within the upstream transcription unit. To ask more directly about the relationship of the tandemness of these genes to their transcription, we have constructed a minirepeat containing two identifiable test genes, with or without enhancer(s). On integration into the URA3 locus, these genes were transcribed by RNA polymerase I. A single enhancer effectively stimulated transcription of both genes by 10- to 30-fold, even when it was located upstream of both or downstream of both. Two enhancers had roughly additive effects. These results suggest a model of enhancer function in tandemly repeated genes.

GABA induction of the Saccharomyces cerevisiae UGA4 gene depends on the quality of the carbon source: Role of the key transcription factors acting in this process

2012 ◽  
Vol 421 (3) ◽  
pp. 572-577 ◽  
Author(s):  
Carolina E. Levi ◽  
Sabrina B. Cardillo ◽  
Santiago Bertotti ◽  
Cristian Ríos ◽  
Susana Correa García ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcription Factors ◽  
Carbon Source

scholarly journals Evidence that intergenic spacer repeats of Drosophila melanogaster rRNA genes function as X-Y pairing sites in male meiosis, and a general model for achiasmatic pairing.

Genetics ◽  
1992 ◽  
Vol 132 (2) ◽  
pp. 529-544 ◽  
Author(s):  
B D McKee ◽  
L Habera ◽  
J A Vrana
Keyword(s):  
Drosophila Melanogaster ◽  
Topoisomerase I ◽  
Meiotic Chromosome ◽  
Intergenic Spacer ◽  
Transcription Unit ◽  
P Element ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Meiotic Pairing ◽  
Rrna Transcription

Abstract In Drosophila melanogaster males, X-Y meiotic chromosome pairing is mediated by the nucleolus organizers (NOs) which are located in the X heterochromatin (Xh) and near the Y centromere. Deficiencies for Xh disrupt X-Y meiotic pairing and cause high frequencies of X-Y nondisjunction. Insertion of cloned rRNA genes on an Xh- chromosome partially restores normal X-Y pairing and disjunction. To map the sequences within an inserted, X-linked rRNA gene responsible for stimulating X-Y pairing, partial deletions were generated by P element-mediated destabilization of the insert. Complete deletions of the rRNA transcription unit did not interfere with the ability to stimulate X-Y pairing as long as most of the intergenic spacer (IGS) remained. Within groups of deletions that lacked the entire transcription unit and differed only in length of residual IGS material, pairing ability was proportional to the dose of 240-bp intergenic spacer repeats. Deletions of the complete rRNA transcription unit or the 28S sequences alone blocked nucleolus formation, as determined by binding of an antinucleolar antibody, yet did not interfere with pairing ability, suggesting that X-Y pairing may not be mechanistically related to nucleolus formation. A model for achiasmatic pairing in Drosophila males based upon the combined action of topoisomerase I and a strand transferase is proposed.

scholarly journals Compartmentation of the Nucleolar Processing Proteins in the Granular Component Is a CK2-driven Process

2006 ◽  
Vol 17 (6) ◽  
pp. 2537-2546 ◽  
Author(s):  
Emilie Louvet ◽  
Henriette Roberte Junéra ◽  
Isabelle Berthuy ◽  
Danièle Hernandez-Verdun
Keyword(s):  
Binding Sites ◽  
Protein Complexes ◽  
Rrna Processing ◽  
Granular Component ◽  
Permeabilized Cells ◽  
Rrna Transcription ◽  
Transcription Sites ◽  
Protein B23 ◽  
Nucleolar Components

To analyze the compartmentation of nucleolar protein complexes, the mechanisms controlling targeting of nucleolar processing proteins onto rRNA transcription sites has been investigated. We studied the reversible disconnection of transcripts and processing proteins using digitonin-permeabilized cells in assays capable of promoting nucleolar reorganization. The assays show that the dynamics of nucleolar reformation is ATP/GTP-dependent, sensitive to temperature, and CK2-driven. We further demonstrate the role of CK2 on the rRNA-processing protein B23. Mutation of the major CK2 site on B23 induces reorganization of nucleolar components that separate from each other. This was confirmed in assays using extracts containing B23 mutated in the CK2-binding sites. We propose that phosphorylation controls the compartmentation of the rRNA-processing proteins and that CK2 is involved in this process.

The Role of Sas2, an Acetyltransferase Homologue of Saccharomyces cerevisiae, in Silencing and ORC Function

Genetics ◽  
1997 ◽  
Vol 145 (4) ◽  
pp. 923-934 ◽  
Author(s):  
Ann E Ehrenhofer-Murray ◽  
David H Rivier ◽  
Jasper Rine
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Binding Sites ◽  
Origin Recognition Complex ◽  
Consensus Sequence ◽  
Opposing Effects ◽  
Regulatory Sites ◽  
Origin Recognition

Silencing at the cryptic mating-type loci HML and HMR of Saccharomyces cerevisiae requires regulatory sites called silencers. Mutations in the Rap1 and Abf1 binding sites of the HMR-E silencer (HMR  a-e**) cause the silencer to be nonfunctional, and hence, cause derepression of HMR. Here, we have isolated and characterized mutations in SAS2 as second-site suppressors of the silencing defect of HMR  a-e**. Silencing conferred by the removal of SAS2 (sas2Δ) depended upon the integrity of the ARS consensus sequence of the HMR-E silencer, thus arguing for an involvement of the origin recognition complex (ORC). Restoration of silencing by sas2Δ required ORC2 and ORC5, but not SIR1 or RAP1. Furthermore, sas2Δ suppressed the·temperature sensitivity, but not the silencing defect of orc2-1 and orc5-1. Moreover, sas2Δ had opposing effects on silencing of HML and HMR. The putative Sas2 protein bears similarities to known protein acetyltransferases. Several models for the role of Sas2 in silencing are discussed.

scholarly journals Repositioning the Sm-binding site in S. cerevisiae telomerase RNA reveals RNP organizational flexibility and Sm-directed 3′-end formation

2017 ◽  
Author(s):  
Evan P. Hass ◽  
David C. Zappulla
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Binding Site ◽  
Strong Evidence ◽  
Binding Sites ◽  
Telomerase Rna ◽  
Telomeric Dna ◽  
Protein Subunits ◽  
Yeast Telomerase ◽  
Rna Biogenesis

ABSTRACTTelomerase RNA contains a template for synthesizing telomeric DNA by reverse transcription and has been proposed to act as a flexible scaffold for holoenzyme protein subunits in the RNP. In Saccharomyces cerevisiae, the telomerase subunits Est1 and Ku bind to the telomerase RNA, TLC1, and it has been shown that these proteins still function when their binding sites are repositioned within the RNA. TLC1 is also bound by the Sm7 protein complex, which is required for stabilization of the predominant, non-polyadenylated (poly(A)–) TLC1 isoform. Here, we first show that Sm7 can perform this function even when its binding site is repositioned via circular permutation to several different positions within TLC1, further supporting the conclusion that the telomerase holoenzyme is organizationally flexible. Next, we tested the hypothesis that the location of the Sm7-binding site relative to the 3′ end is contrastingly important. When we moved the Sm site to locations 5′ of its native position, we observed that this stabilized shorter forms of poly(A)– TLC1 in a manner precisely corresponding to how far upstream the Sm site was moved. This provides strong evidence that the location of Sm7 binding to TLC1 controls where the mature poly(A)– 3′ end is formed. In summary, our results show that Sm7 and the 3′ end of yeast telomerase RNA comprise an organizationally flexible module within the telomerase RNP and provide insights into the mechanistic role of Sm7 in telomerase RNA biogenesis.

scholarly journals Key Role of Ser562/661 in Snf1-Dependent Regulation of Cat8p in Saccharomyces cerevisiae and Kluyveromyces lactis

2004 ◽  
Vol 24 (10) ◽  
pp. 4083-4091 ◽  
Author(s):  
Godefroid Charbon ◽  
Karin D. Breunig ◽  
Ruddy Wattiez ◽  
Jean Vandenhaute ◽  
Isabelle Noël-Georis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Target Genes ◽  
Kluyveromyces Lactis ◽  
Active Form ◽  
Phosphorylation Site ◽  
Carbon Sources ◽  
Mutant Form ◽  
Zinc Cluster

ABSTRACT Utilization of nonfermentable carbon sources by Kluyveromyces lactis and Saccharomyces cerevisiae requires the Snf1p kinase and the Cat8p transcriptional activator, which binds to carbon source-responsive elements of target genes. We demonstrate that KlSnf1p and KlCat8p from K. lactis interact in a two-hybrid system and that the interaction is stronger with a kinase-dead mutant form of KlSnf1p. Of two putative phosphorylation sites in the KlCat8p sequence, serine 661 was identified as a key residue governing KlCat8p regulation. Serine 661 is located in the middle homology region, a regulatory domain conserved among zinc cluster transcription factors, and is part of an Snf1p consensus phosphorylation site. Single mutations at this site are sufficient to completely change the carbon source regulation of the KlCat8p transactivation activity observed. A serine-to-glutamate mutant form mimicking constitutive phosphorylation results in a nearly constitutively active form of KlCat8p, while a serine-to-alanine mutation has the reverse effect. Furthermore, it is shown that KlCat8p phosphorylation depends on KlSNF1. The Snf1-Cat8 connection is evolutionarily conserved: mutation of corresponding serine 562 of ScCat8p gave similar results in S. cerevisiae. The enhanced capacity of ScCat8S562E to suppress the phenotype caused by snf1 strengthens the hypothesis of direct phosphorylation of Cat8p by Snf1p. Unlike that of S. cerevisiae ScCAT8, KlCAT8 transcription is not carbon source regulated, illustrating the prominent role of posttranscriptional regulation of Cat8p in K. lactis.

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