Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P23193 (transcription elongation factor)
 739 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The RPB9 subunit of RNA polymerase II regulates transcription elongation activity and is required for the action of the transcription elongation factor, TFIIS. RPB9 comprises two zinc ribbon domains joined by a conserved linker region. The C-terminal zinc ribbon is similar in sequence to that found in TFIIS. To elucidate the relationship between the structure and transcription elongation function of RPB9, we initiated a mutagenesis study on the Saccharomyces cerevisiae homologue. The individual zinc ribbon domains, in isolation or in combination, could not stimulate transcription by a polymerase lacking RPB9, pol IIDelta9. Mutations in the N-terminal zinc ribbon had little effect on transcription activity. By contrast, mutations in the acidic loop that connects the second and third beta-strands of the C-terminal zinc ribbon were completely inactive for transcription. Interestingly, the analogous residues in TFIIS are also critical for elongation activity. A conserved charged stretch in the linker region (residues 89-95, DPTLPR) mediated the interaction with RNA polymerase II.
 ...
PMID:Yeast RNA polymerase II subunit RPB9. Mapping of domains required for transcription elongation. 1064 77

The Rpb6 subunit of RNA polymerase II is one of the five subunits common to three forms of eukaryotic RNA polymerase. Deletion and truncation analyses of the rpb6 gene in the fission yeast Schizosaccharomyces pombe indicated that Rpb6, consisting of 142 amino acid residues, is an essential protein for cell viability, and the essential region is located in the C-terminal half between residues 61 and 139. After random mutagenesis, a total of 14 temperature-sensitive mutants were isolated, each carrying a single (or double in three cases and triple in one) mutation. Four mutants each carrying a single mutation in the essential region were sensitive to 6-azauracil (6AU), which inhibits transcription elongation by depleting the intracellular pool of GTP and UTP. Both 6AU sensitivity and temperature-sensitive phenotypes of these rpb6 mutants were suppressed by overexpression of TFIIS, a transcription elongation factor. In agreement with the genetic studies, the mutant RNA polymerases containing the mutant Rpb6 subunits showed reduced affinity for TFIIS, as measured by a pull-down assay of TFIIS-RNA polymerase II complexes using a fusion form of TFIIS with glutathione S-transferase. Moreover, the direct interaction between TFIIS and RNA polymerase II was competed by the addition of Rpb6. Taken together, the results lead us to propose that Rpb6 plays a role in the interaction between RNA polymerase II and the transcription elongation factor TFIIS.
 ...
PMID:The Rpb6 subunit of fission yeast RNA polymerase II is a contact target of the transcription elongation factor TFIIS. 1064 12

TFIIS is a transcription elongation factor that consists of three domains. We have previously solved the structures of domains II and III, which stimulate arrested polymerase II elongation complexes in order to resume transcription. Domain I is conserved in evolution from yeast to human species and is homologous to the transcription factors elongin A and CRSP70. Domain I also interacts with the transcriptionally active RNA polymerase II holoenzyme and therefore, may have a function unrelated to the previously described transcription elongation activity of TFIIS. We have solved the structure of domain I of yeast TFIIS using NMR spectroscopy. Domain I is a compact four-helix bundle that is structurally independent of domains II and III of the TFIIS. Using the yeast structure as a template, we have modeled the homologous domains from elongin A and CRSP70 and identified a conserved positively charged patch on the surface of all three proteins, which may be involved in conserved functional interactions with the transcriptional machinery.
 ...
PMID:Structure of a conserved domain common to the transcription factors TFIIS, elongin A, and CRSP70. 1081 49

RNA polymerase II lacking the Rpb9 subunit uses alternate transcription initiation sites in vitro and in vivo and is unable to respond to the transcription elongation factor TFIIS in vitro. Here, we show that RPB9 has a synthetic phenotype with the TFIIS gene. Disruption of RPB9 in yeast also resulted in sensitivity to 6-azauracil, which is a phenotype linked to defects in transcription elongation. Expression of the TFIIS gene on a high-copy plasmid partially suppressed the 6-azauracil sensitivity of Deltarpb9 cells. We set out to determine the relevant cellular role of yeast Rpb9 by assessing the ability of 20 different site-directed and deletion mutants of RPB9 to complement the initiation and elongation defects of Deltarpb9 cells in vivo. Rpb9 is composed of two zinc ribbons. The N-terminal zinc ribbon restored the wild-type pattern of initiation start sites, but was unable to complement the growth defects associated with defects in elongation. Most of the site-directed mutants complemented the elongation-specific growth phenotypes and reconstituted the normal pattern of transcription initiation sites. The anti-correlation between the growth defects of cells disrupted for RPB9 and the selection of transcription start sites suggests that this is not the primary cellular role for Rpb9. Genome-wide transcription profiling of Deltarpb9 cells revealed only a few changes, predominantly in genes related to metabolism.
 ...
PMID:RNA polymerase II subunit Rpb9 regulates transcription elongation in vivo. 1093 84

Yeast cells lacking transcription elongation factor genes such as PPR2 (TFIIS) and ELP (Elongator) are viable and show deleterious phenotypes only when transcription is rendered less effective by RNA polymerase mutations or by decreasing nucleotide pools. Here we demonstrate that deletion of the CTK1 gene, encoding the kinase subunit of RNA polymerase II carboxy-terminal domain kinase I (CTDK-I), is synthetically lethal when combined with deletion of PPR2 or ELP genes. The inviability of ctk1 elp3 double mutants can be rescued by expression of an Elp3 mutant that has retained its ability to form the Elongator complex but has severely diminished histone acetyltransferase activity, suggesting that the functional overlap between CTDK-I and Elongator is in assembly of RNA polymerase II elongation complexes. Our results suggest that CTDK-I plays an important role in transcriptional elongation in vivo, possibly by creating a form of RNA polymerase that is less prone to transcriptional arrest.
 ...
PMID:Involvement of yeast carboxy-terminal domain kinase I (CTDK-I) in transcription elongation in vivo. 1131 53

The RNA polymerase II (pol II) transcription complex undergoes a structural transition around registers 20-25, as indicated by ExoIII footprinting analyses. We have employed a highly purified system to prepare pol II complexes stalled at very precise positions during the initial stage of transcript elongation. Using potassium permanganate we analyzed the open region ('transcription bubble') of complexes stalled between registers 15 and 35. We found that from register 15 up to 25 the transcription bubble expands concomitantly with RNA synthesis. At registers 26 and 27 the bubble has a high tendency to retract at the leading edge. Addition of transcription elongation factor TFIIS re-extends the bubble to the stall site, resulting in complexes competent for transcript elongation. These findings are discussed in the light of the recently determined structures for RNA polymerases.
 ...
PMID:Analysis of the open region of RNA polymerase II transcription complexes in the early phase of elongation. 1143 15

TFIIS is a transcription elongation factor for RNA polymerase II (pol II), which can suppress ribonucleotide misincorporation. We reconstituted transcription complexes in a highly purified pol II system on adenovirus Major-Late promoter constructs. We noted that these complexes have a high propensity for read-through upon GTP omission. Read-through occurred during the early stages at all registers analyzed. Addition of TFIIS reversed read-through of productive elongation complexes, which indicated that it was due to misincorporation. However, before register 13 transcription complexes were insensitive to TFIIS. These findings are discussed with respect to the structural models for pol II and we propose that TFIIS action is linked to the RNA:DNA hybrid.
 ...
PMID:RNA polymerase II complexes in the very early phase of transcription are not susceptible to TFIIS-induced exonucleolytic cleavage. 1203 15

The Euplotes crassus macronuclear DNA molecule containing the conjugation-specific conN1 gene has been sequenced, along with a cDNA clone. The results indicate that the conN1 gene encodes a protein similar to the transcription elongation factor TFIIS proteins identified in other eukaryotes.
 ...
PMID:The Euplotes crassus conjugation-specific conN1 gene encodes a transcription elongation factor TFIIS-like protein. 1209 10

The histone methyltransferase Set2, which specifically methylates lysine 36 of histone H3, has been shown to repress transcription upon tethering to a heterologous promoter. However, the mechanism of targeting and the consequence of Set2-dependent methylation have yet to be demonstrated. We sought to identify the protein components associated with Set2 to gain some insights into the in vivo function of this protein. Mass spectrometry analysis of the Set2 complex, purified using a tandem affinity method, revealed that RNA polymerase II (pol II) is associated with Set2. Immunoblotting and immunoprecipitation using antibodies against subunits of pol II confirmed that the phosphorylated form of pol II is indeed an integral part of the Set2 complex. Gst-Set2 preferentially binds to CTD synthetic peptides phosphorylated at serine 2, and to a lesser extent, serine 5 phosphorylated peptides, but has no affinity for unphosphorylated CTD, suggesting that Set2 associates with the elongating form of the pol II. Furthermore, we show that set2Delta ppr2Delta double mutants (PPR2 encodes TFIIS, a transcription elongation factor) are synthetically hypersensitive to 6-azauracil, and that deletions in the CTD reduce in vivo levels of H3 lysine 36 methylation. Collectively, these results suggest that Set2 is involved in regulating transcription elongation through its direct contact with pol II.
 ...
PMID:The Set2 histone methyltransferase functions through the phosphorylated carboxyl-terminal domain of RNA polymerase II. 1251 61

We have examined the localization and targeting of the RNA polymerase II (pol II) transcription elongation factor TFIIS in amphibian oocyte nuclei by immunofluorescence. Using a novel antibody against Xenopus TFIIS the major sites of immunostaining were found to be Cajal bodies, nuclear organelles that also contain pol II. Small granular structures attached to lampbrush chromosomes were also specifically stained but the transcriptionally active loops were not. Similar localization patterns were found for the newly synthesized myc-tagged TFIIS produced after injection of synthetic transcripts into the cytoplasm. The basis of the rapid and preferential targeting of TFIIS to Cajal bodies was investigated by examining the effects of deletion and site-specific mutations. Multiple regions of TFIIS contributed to efficient targeting including the domain required for its binding to pol II. The localization of TFIIS in Cajal bodies, and in particular the apparent involvement of pol II binding in achieving it, offer further support for a model in which Cajal bodies function in the preassembly of the transcriptional machinery. Although our findings are therefore consistent with TFIIS playing a role in early events of the transcription cycle, they also suggest that this elongation factor is not generally required during transcription in oocytes.
 ...
PMID:Subnuclear localization and Cajal body targeting of transcription elongation factor TFIIS in amphibian oocytes. 1263 38


<< Previous 1 2 3 4 5 Next >>