scholarly journals Mutations in RNA Polymerase II and Elongation Factor SII Severely Reduce mRNA Levels in Saccharomyces cerevisiae

1998 ◽  
Vol 18 (10) ◽  
pp. 5771-5779 ◽  
Author(s):  
J. Cale Lennon ◽  
Megan Wind ◽  
Laura Saunders ◽  
M. Benjamin Hock ◽  
Daniel Reines

ABSTRACT Elongation factor SII interacts with RNA polymerase II and enables it to transcribe through arrest sites in vitro. The set of genes dependent upon SII function in vivo and the effects on RNA levels of mutations in different components of the elongation machinery are poorly understood. Using yeast lacking SII and bearing a conditional allele of RPB2, the gene encoding the second largest subunit of RNA polymerase II, we describe a genetic interaction between SII and RPB2. An SII gene disruption or therpb2-10 mutation, which yields an arrest-prone enzyme in vitro, confers sensitivity to 6-azauracil (6AU), a drug that depresses cellular nucleoside triphosphates. Cells with both mutations had reduced levels of total poly(A)+ RNA and specific mRNAs and displayed a synergistic level of drug hypersensitivity. In cells in which the SII gene was inactivated, rpb2-10 became dominant, as if template-associated mutant RNA polymerase II hindered the ability of wild-type polymerase to transcribe. Interestingly, while 6AU depressed RNA levels in both wild-type and mutant cells, wild-type cells reestablished normal RNA levels, whereas double-mutant cells could not. This work shows the importance of an optimally functioning elongation machinery for in vivo RNA synthesis and identifies an initial set of candidate genes with which SII-dependent transcription can be studied.

1992 ◽  
Vol 12 (9) ◽  
pp. 4142-4152
Author(s):  
J Archambault ◽  
F Lacroute ◽  
A Ruet ◽  
J D Friesen

Little is known about the regions of RNA polymerase II (RNAPII) that are involved in the process of transcript elongation and interaction with elongation factors. One elongation factor, TFIIS, stimulates transcript elongation by binding to RNAPII and facilitating its passage through intrinsic pausing sites in vitro. In Saccharomyces cerevisiae, TFIIS is encoded by the PPR2 gene. Deletion of PPR2 from the yeast genome is not lethal but renders cells sensitive to the uracil analog 6-azauracil (6AU). Here, we show that mutations conferring 6AU sensitivity can also be isolated in the gene encoding the largest subunit of S. cerevisiae RNAPII (RPO21). A screen for mutations in RPO21 that confer 6AU sensitivity identified seven mutations that had been generated by either linker-insertion or random chemical mutagenesis. All seven mutational alterations are clustered within one region of the largest subunit that is conserved among eukaryotic RNAPII. The finding that six of the seven rpo21 mutants failed to grow at elevated temperature underscores the importance of this region for the functional and/or structural integrity of RNAPII. We found that the 6AU sensitivity of the rpo21 mutants can be suppressed by increasing the dosage of the wild-type PPR2 gene, presumably as a result of overexpression of TFIIS. These results are consistent with the proposal that in the rpo21 mutants, the formation of the RNAPII-TFIIS complex is rate limiting for the passage of the mutant enzyme through pausing sites. In addition to implicating a region of the largest subunit of RNAPII in the process of transcript elongation, our observations provide in vivo evidence that TFIIS is involved in transcription by RNAPII.


1992 ◽  
Vol 12 (9) ◽  
pp. 4142-4152 ◽  
Author(s):  
J Archambault ◽  
F Lacroute ◽  
A Ruet ◽  
J D Friesen

Little is known about the regions of RNA polymerase II (RNAPII) that are involved in the process of transcript elongation and interaction with elongation factors. One elongation factor, TFIIS, stimulates transcript elongation by binding to RNAPII and facilitating its passage through intrinsic pausing sites in vitro. In Saccharomyces cerevisiae, TFIIS is encoded by the PPR2 gene. Deletion of PPR2 from the yeast genome is not lethal but renders cells sensitive to the uracil analog 6-azauracil (6AU). Here, we show that mutations conferring 6AU sensitivity can also be isolated in the gene encoding the largest subunit of S. cerevisiae RNAPII (RPO21). A screen for mutations in RPO21 that confer 6AU sensitivity identified seven mutations that had been generated by either linker-insertion or random chemical mutagenesis. All seven mutational alterations are clustered within one region of the largest subunit that is conserved among eukaryotic RNAPII. The finding that six of the seven rpo21 mutants failed to grow at elevated temperature underscores the importance of this region for the functional and/or structural integrity of RNAPII. We found that the 6AU sensitivity of the rpo21 mutants can be suppressed by increasing the dosage of the wild-type PPR2 gene, presumably as a result of overexpression of TFIIS. These results are consistent with the proposal that in the rpo21 mutants, the formation of the RNAPII-TFIIS complex is rate limiting for the passage of the mutant enzyme through pausing sites. In addition to implicating a region of the largest subunit of RNAPII in the process of transcript elongation, our observations provide in vivo evidence that TFIIS is involved in transcription by RNAPII.


2001 ◽  
Vol 276 (15) ◽  
pp. 12266-12273 ◽  
Author(s):  
Wenxiang Wei ◽  
Dorjbal Dorjsuren ◽  
Yong Lin ◽  
Weiping Qin ◽  
Takahiro Nomura ◽  
...  

The general transcription factor IIF (TFIIF) assembled in the initiation complex, and RAP30 of TFIIF, have been shown to associate with RNA polymerase II (pol II), although it remains unclear which pol II subunit is responsible for the interaction. We examined whether TFIIF interacts with RNA polymerase II subunit 5 (RPB5), the exposed domain of which binds transcriptional regulatory factors such as hepatitis B virus X protein and a novel regulatory protein, RPB5-mediating protein. The results demonstrated that RPB5 directly binds RAP30in vitrousing purified recombinant proteins andin vivoin COS1 cells transiently expressing recombinant RAP30 and RPB5. The RAP30-binding region was mapped to the central region (amino acids (aa) 47–120) of RPB5, which partly overlaps the hepatitis B virus X protein-binding region. Although the middle part (aa 101–170) and the N-terminus (aa 1–100) of RAP30 independently bound RPB5, the latter was not involved in the RPB5 binding when RAP30 was present in TFIIF complex. Scanning of the middle part of RAP30 by clustered alanine substitutions and then point alanine substitutions pinpointed two residues critical for the RPB5 binding inin vitroandin vivoassays. Wild type but not mutants Y124A and Q131A of RAP30 coexpressed with FLAG-RAP74 efficiently recovered endogenous RPB5 to the FLAG-RAP74-bound anti-FLAG M2 resin. The recovered endogenous RPB5 is assembled in pol II as demonstrated immunologically. Interestingly, coexpression of the central region of RPB5 and wild type RAP30 inhibited recovery of endogenous pol II to the FLAG-RAP74-bound M2 resin, strongly suggesting that the RAP30-binding region of RPB5 inhibited the association of TFIIF and pol II. The exposed domain of RPB5 interacts with RAP30 of TFIIF and is important for the association between pol II and TFIIF.


1990 ◽  
Vol 10 (10) ◽  
pp. 5433-5441
Author(s):  
B Y Ahn ◽  
P D Gershon ◽  
E V Jones ◽  
B Moss

Eucaryotic transcription factors that stimulate RNA polymerase II by increasing the efficiency of elongation of specifically or randomly initiated RNA chains have been isolated and characterized. We have identified a 30-kilodalton (kDa) vaccinia virus-encoded protein with apparent homology to SII, a 34-kDa mammalian transcriptional elongation factor. In addition to amino acid sequence similarities, both proteins contain C-terminal putative zinc finger domains. Identification of the gene, rpo30, encoding the vaccinia virus protein was achieved by using antibody to the purified viral RNA polymerase for immunoprecipitation of the in vitro translation products of in vivo-synthesized early mRNA selected by hybridization to cloned DNA fragments of the viral genome. Western immunoblot analysis using antiserum made to the vaccinia rpo30 protein expressed in bacteria indicated that the 30-kDa protein remains associated with highly purified viral RNA polymerase. Thus, the vaccinia virus protein, unlike its eucaryotic homolog, is an integral RNA polymerase subunit rather than a readily separable transcription factor. Further studies showed that the expression of rpo30 is regulated by dual early and later promoters.


1990 ◽  
Vol 10 (10) ◽  
pp. 5433-5441 ◽  
Author(s):  
B Y Ahn ◽  
P D Gershon ◽  
E V Jones ◽  
B Moss

Eucaryotic transcription factors that stimulate RNA polymerase II by increasing the efficiency of elongation of specifically or randomly initiated RNA chains have been isolated and characterized. We have identified a 30-kilodalton (kDa) vaccinia virus-encoded protein with apparent homology to SII, a 34-kDa mammalian transcriptional elongation factor. In addition to amino acid sequence similarities, both proteins contain C-terminal putative zinc finger domains. Identification of the gene, rpo30, encoding the vaccinia virus protein was achieved by using antibody to the purified viral RNA polymerase for immunoprecipitation of the in vitro translation products of in vivo-synthesized early mRNA selected by hybridization to cloned DNA fragments of the viral genome. Western immunoblot analysis using antiserum made to the vaccinia rpo30 protein expressed in bacteria indicated that the 30-kDa protein remains associated with highly purified viral RNA polymerase. Thus, the vaccinia virus protein, unlike its eucaryotic homolog, is an integral RNA polymerase subunit rather than a readily separable transcription factor. Further studies showed that the expression of rpo30 is regulated by dual early and later promoters.


2021 ◽  
Author(s):  
Ülkü Uzun ◽  
Thomas Brown ◽  
Harry Fischl ◽  
Andrew Angel ◽  
Jane Mellor

AbstractSpt4 is a transcription elongation factor, with homologues in organisms with nucleosomes. Structural and in vitro studies implicate Spt4 in transcription through nucleosomes, yet the in vivo function of Spt4 is unclear. Here we assessed the precise position of Spt4 during transcription and the consequences of loss of Spt4 on RNA polymerase II (RNAPII) dynamics and nucleosome positioning in Saccharomyces cerevisiae. In the absence of Spt4, the spacing between gene-body nucleosomes increases and RNAPII accumulates upstream of the nucleosomal dyad, most dramatically at nucleosome +2. Spt4 associates with elongating RNAPII early in transcription and its association dynamically changes depending on nucleosome positions. Together, our data show that Spt4 regulates early elongation dynamics, participates in co-transcriptional nucleosome positioning, and promotes RNAPII movement through the gene-body nucleosomes, especially the +2 nucleosome.


1992 ◽  
Vol 12 (5) ◽  
pp. 2078-2090
Author(s):  
N F Marshall ◽  
D H Price

We have examined elongation by RNA polymerase II initiated at a promoter and have identified two classes of elongation complexes. Following initiation at a promoter, all polymerase molecules enter an abortive mode of elongation. Abortive elongation is characterized by the rapid generation of short transcripts due to pausing of the polymerase followed by termination of transcription. Termination of the early elongation complexes can be suppressed by the addition of 250 mM KCl or 1 mg of heparin per ml soon after initiation. Elongation complexes of the second class carry out productive elongation in which long transcripts can be synthesized. Productive elongation complexes are derived from early paused elongation complexes by the action of a factor which we call P-TEF (positive transcription elongation factor). P-TEF is inhibited by 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole at concentrations which have no effect on the initiation of transcription. By using templates immobilized on paramagnetic particles, we show that isolated preinitiation complexes lack P-TEF and give rise to transcription complexes which can carry out only abortive elongation. The ability to carry out productive elongation can be restored to isolated transcription complexes by the addition of P-TEF after initiation. A model is presented which describes the role of elongation factors in the formation and maintenance of elongation complexes. The model is consistent with the available in vivo data concerning control of elongation and is used to predict the outcome of other potential in vitro and in vivo experiments.


Genetics ◽  
1995 ◽  
Vol 140 (2) ◽  
pp. 599-613 ◽  
Author(s):  
W J Brickey ◽  
A L Greenleaf

Abstract To understand the in vivo function of the unique and conserved carboxy-terminal repeat domain (CTD) of RNA polymerase II largest subunit (RpII215), we have studied RNA polymerase II biosynthesis, activity and genetic function in Drosophila RpII215 mutants that possessed all (C4), half (W81) or none (IIt) of the CTD repeats. We have discovered that steady-state mRNA levels from transgenes encoding a fully truncated, CTD-less subunit (IIt) are essentially equal to wild-type levels, whereas the levels of the CTD-less subunit itself and the amount of polymerase harboring it (Pol IIT) are significantly lower than wild type. In contrast, for the half-CTD mutant (W81), steady-state mRNA levels are somewhat lower than for wild type or IIt, while W81 subunit and polymerase amounts are much less than wild type. Finally, we have tested genetically the ability of CTD mutants to complement (rescue) partially functional RpII215 alleles and have found that IIt fails to complement whereas W81 complements partially to completely. These results suggest that removal of the entire CTD renders polymerase completely defective in vivo, whereas eliminating half of the CTD results in a polymerase with significant in vivo activity.


2009 ◽  
Vol 29 (20) ◽  
pp. 5455-5464 ◽  
Author(s):  
Kira Glover-Cutter ◽  
Stéphane Larochelle ◽  
Benjamin Erickson ◽  
Chao Zhang ◽  
Kevan Shokat ◽  
...  

ABSTRACT The function of human TFIIH-associated Cdk7 in RNA polymerase II (Pol II) transcription and C-terminal domain (CTD) phosphorylation was investigated in analogue-sensitive Cdk7 as/as mutant cells where the kinase can be inhibited without disrupting TFIIH. We show that both Cdk7 and Cdk9/PTEFb contribute to phosphorylation of Pol II CTD Ser5 residues on transcribed genes. Cdk7 is also a major kinase of CTD Ser7 on Pol II at the c-fos and U snRNA genes. Furthermore, TFIIH and recombinant Cdk7-CycH-Mat1 as well as recombinant Cdk9-CycT1 phosphorylated CTD Ser7 and Ser5 residues in vitro. Inhibition of Cdk7 in vivo suppressed the amount of Pol II accumulated at 5′ ends on several genes including c-myc, p21, and glyceraldehyde-3-phosphate dehydrogenase genes, indicating reduced promoter-proximal pausing or polymerase “leaking” into the gene. Consistent with a 5′ pausing defect, Cdk7 inhibition reduced recruitment of the negative elongation factor NELF at start sites. A role of Cdk7 in regulating elongation is further suggested by enhanced histone H4 acetylation and diminished histone H4 trimethylation on lysine 36—two marks of elongation—within genes when the kinase was inhibited. Consistent with a new role for TFIIH at 3′ ends, it was detected within genes and 3′-flanking regions, and Cdk7 inhibition delayed pausing and transcription termination.


2004 ◽  
Vol 24 (16) ◽  
pp. 7043-7058 ◽  
Author(s):  
Célia Jeronimo ◽  
Marie-France Langelier ◽  
Mahel Zeghouf ◽  
Marilena Cojocaru ◽  
Dominique Bergeron ◽  
...  

ABSTRACT We have programmed human cells to express physiological levels of recombinant RNA polymerase II (RNAPII) subunits carrying tandem affinity purification (TAP) tags. Double-affinity chromatography allowed for the simple and efficient isolation of a complex containing all 12 RNAPII subunits, the general transcription factors TFIIB and TFIIF, the RNAPII phosphatase Fcp1, and a novel 153-kDa polypeptide of unknown function that we named RNAPII-associated protein 1 (RPAP1). The TAP-tagged RNAPII complex is functionally active both in vitro and in vivo. A role for RPAP1 in RNAPII transcription was established by shutting off the synthesis of Ydr527wp, a Saccharomyces cerevisiae protein homologous to RPAP1, and demonstrating that changes in global gene expression were similar to those caused by the loss of the yeast RNAPII subunit Rpb11. We also used TAP-tagged Rpb2 with mutations in fork loop 1 and switch 3, two structural elements located strategically within the active center, to start addressing the roles of these elements in the interaction of the enzyme with the template DNA during the transcription reaction.


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