scholarly journals An integrated model for termination of RNA polymerase III transcription

2021 ◽  
Author(s):  
Juanjuan Xie ◽  
Umberto Aiello ◽  
Yves Clement ◽  
Nouhou Haidara ◽  
Mathias Girbig ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Transcription Termination ◽  
Rna Polymerase Iii ◽  
In Vitro Transcription ◽  
Cis Acting ◽  
Template Strand ◽  
Polymerase Iii ◽  
Genome Wide ◽  
Fail Safe

RNA polymerase III (RNAPIII) synthesizes essential and abundant non-coding RNAs such as tRNAs. Controlling RNAPIII span of activity by accurate and efficient termination is a challenging necessity to ensure robust gene expression and to prevent conflicts with other DNA-associated machineries. The mechanism of RNAPIII termination is believed to be simpler than that of other eukaryotic RNA polymerases, solely relying on the recognition of a T-tract in the non-template strand. Here we combine high-resolution genome-wide analyses and in vitro transcription termination assays to revisit the mechanism of RNAPIII transcription termination in budding yeast. We show that T-tracts are necessary but not always sufficient for termination and that secondary structures of the nascent RNAs are important auxiliary cis-acting elements. Moreover, we show that the helicase Sen1 plays a key role in a fail-safe termination pathway. Our results provide a comprehensive model illustrating how multiple mechanisms cooperate to ensure efficient RNAPIII transcription termination.

scholarly journals Termination-altering mutations in the second-largest subunit of yeast RNA polymerase III.

1995 ◽  
Vol 15 (3) ◽  
pp. 1467-1478 ◽  
Author(s):  
S A Shaaban ◽  
B M Krupp ◽  
B D Hall
Keyword(s):  
Amino Acid ◽  
Rna Polymerase ◽  
Transcription Initiation ◽  
Transcription Termination ◽  
Rna Polymerase Iii ◽  
In Vitro Transcription ◽  
The Other ◽  
Polymerase Iii

In order to identify catalytically important amino acid changes within the second-largest subunit of yeast RNA polymerase III, we mutagenized selected regions of its gene (RET1) and devised in vivo assays for both increased and decreased transcription termination by this enzyme. Using as the reporter gene a mutant SUP4-o tRNA gene that in one case terminates prematurely and in the other case fails to terminate, we screened mutagenized RET1 libraries for reduced and increased transcription termination, respectively. The gain in suppression phenotype was in both cases scored as a reduction in the accumulation of red pigment in yeast strains harboring the ade2-1 ochre mutation. Termination-altering mutations were obtained in regions of the RET1 gene encoding amino acids 300 to 325, 455 to 486, 487 to 521, and 1061 to 1082 of the protein. In degree of amino acid sequence conservation, these range from highly variable in the first to highly conserved in the last two regions. Residues 300 to 325 yielded mainly reduced-termination mutants, while in region 1061 to 1082, increased-termination mutants were obtained exclusively. All mutants recovered, while causing gain of suppression with one SUP4 allele, brought about a reduction in suppression with the other allele, thus confirming that the phenotype is due to altered termination rather than an elevated level of transcription initiation. In vitro transcription reactions performed with extracts from several strong mutants demonstrated that the mutant polymerases respond to RNA terminator sequences in a manner that matches their in vivo termination phenotypes.

scholarly journals ret1-1, a yeast mutant affecting transcription termination by RNA polymerase III.

Genetics ◽  
1990 ◽  
Vol 125 (2) ◽  
pp. 293-303
Author(s):  
P James ◽  
B D Hall
Keyword(s):  
Rna Polymerase ◽  
Transcription Termination ◽  
Rna Polymerase Iii ◽  
In Vitro Transcription ◽  
Polymerase Iii ◽  
Reconstituted System ◽  
Gene Fractionation ◽  
Yeast Mutants

Abstract In eukaryotes, extended tracts of T residues are known to signal the termination of RNA polymerase III transcription. However, it is not understood how the transcription complex interacts with this signal. We have developed a selection system in yeast that uses ochre suppressors weakened by altered transcription termination signals to identify mutations in the proteins involved in termination of transcription by RNA polymerase III. Over 7600 suppression-plus yeast mutants were selected and screened, leading to the identification of one whose effect is mediated transcriptionally. The ret1-1 mutation arose in conjunction with multiple rare events, including uninduced sporulation, gene amplification, and mutation. In vitro transcription extracts from ret1-1 cells terminate less efficiently at weak transcription termination signals than those from RET1 cells, using a variety of tRNA templates. In vivo this reduced termination efficiency can lead to either an increase or a further decrease in suppressor strength, depending on the location of the altered termination signal present in the suppressor tRNA gene. Fractionation of in vitro transcription extracts and purification of RNA polymerase III has shown that the mutant effect is mediated by highly purified polymerase in a reconstituted system.

scholarly journals Contributions of in vitro transcription to the understanding of human RNA polymerase III transcription

Transcription ◽  
2014 ◽  
Vol 5 (1) ◽  
pp. e27526 ◽  
Author(s):  
Hélène Dumay-Odelot ◽  
Stéphanie Durrieu-Gaillard ◽  
Leyla El Ayoubi ◽  
Camila Parrot ◽  
Martin Teichmann
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Iii ◽  
In Vitro Transcription ◽  
Polymerase Iii

Point mutation associated with hereditary persistence of fetal hemoglobin decreases RNA polymerase III transcription upstream of the affected gamma-globin gene

1986 ◽  
Vol 6 (9) ◽  
pp. 3278-3282
Author(s):  
D P Carlson ◽  
J Ross
Keyword(s):  
Rna Polymerase ◽  
Globin Gene ◽  
Rna Polymerase Iii ◽  
Fetal Hemoglobin ◽  
In Vitro Transcription ◽  
Base Substitution ◽  
Gamma Globin ◽  
Polymerase Iii ◽  
Hemoglobin Production

A base substitution in the 5'-flanking region of a human fetal globin gene is associated with abnormal fetal hemoglobin production. It also reduces by 5- to 10-fold in vitro transcription of the gene by RNA polymerase III. We discuss potential links between polymerase III transcription and abnormal hemoglobin production.

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