Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An RNA polymerase II molecule is associated with the 5' end of the Drosophila melanogaster hsp70 gene under non-heat shock conditions. This polymerase is engaged in transcription but has paused, or arrested, after synthesizing about 25 nucleotides (A. E. Rougvie and J. T. Lis, Cell 54:795-804, 1988). Resumption of elongation by this paused polymerase appears to be the rate-limiting step in hsp70 transcription in uninduced cells. Here we report results of nuclear run-on assays that measure the distribution of elongating and paused RNA polymerase molecules on the hsp70 gene in induced cells. Pausing of polymerase was detected at the 5' end of hsp70 in cells exposed to the intermediate heat shock temperatures of 27 and 30 degrees C. At 30 degrees C, each copy of hsp70 was transcribed approximately five times during the 25-min heat shock that we used. Therefore, once the hsp70 gene is induced to an intermediate level, initiation of transcription by RNA polymerase II remains more rapid than the resumption of elongation by a paused polymerase molecule.
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PMID:RNA polymerase II pauses at the 5' end of the transcriptionally induced Drosophila hsp70 gene. 192 45

Each step in the synthesis of functional transcript by RNA polymerase II provides a level at which gene expression can be regulated. Control over the elongation phase of transcription is a recognized regulatory mechanism in prokaryotes; however, only recently have examples of conditional transcription elongation blockage been reported in eukaryotic cellular genes. In several cases, control over transcription elongation clearly contributes to the regulated expression of these genes. Indeed, reports that transcription by RNA polymerase II is initiated and paused on many Drosophila promoters, prior to induction of gene expression, suggests that release of an arrested polymerase, as opposed to polymerase recruitment to a disengaged promoter, may be the key regulatory step for many genes thought to be controlled by transcription initiation (Rougvie & Lis, 1988). RNA polymerase II undergoes modifications, such as association with ancillary elongation factors and phosphorylation of its large subunit carboxy terminal domain (CTD), at stages subsequent to recruitment to a promoter and establishment of a pre-initiation complex (Reinberg & Roeder, 1987; Rappaport et al., 1987; Payne et al., 1989; Laybourn & Dahmus, 1989). It is possible that modifications such as these, or others occurring prior to, during or following transcription initiation, may alter the holoenzyme's transcription elongation properties, to allow recognition or read-through of elongation block signals within a transcription unit. In this review, we will present features of transcription elongation blockage in several eukaryotic cellular genes in the context of our understanding of attenuation and premature transcription termination in prokaryotic and viral genes. We will also present evidence supporting the model that modifications to the RNA polymerase II transcription complex are pivotal to the control of transcriptional at the level of elongation.
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PMID:Transcription elongation and eukaryotic gene regulation. 219 90

By using a protein-DNA cross-linking method (D. S. Gilmour and J. T. Lis, Mol. Cell. Biol. 5:2009-2018, 1985), we examined the in vivo distribution of RNA polymerase II on the hsp70 heat shock gene in Drosophila melanogaster Schneider line 2 cells. In heat shock-induced cells, a high level of RNA polymerase II was detected on the entire gene, while in noninduced cells, the RNA polymerase II was confined to the 5' end of the hsp70 gene, predominantly between nucleotides -12 and +65 relative to the start of transcription. This association of RNA polymerase II was apparent whether the cross-linking was performed by a 10-min UV irradiation of chilled cells with mercury vapor lamps or by a 40-microsecond irradiation of cells with a high-energy xenon flash lamp. We hypothesize that RNA polymerase II has access to, and a high affinity for, the promoter region of this gene before induction, and this poised RNA polymerase II may be critical in the mechanism of transcription activation.
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PMID:RNA polymerase II interacts with the promoter region of the noninduced hsp70 gene in Drosophila melanogaster cells. 309 67

Heat shock loci in the polytene chromosomes of the fruit fly Drosophila undergo a characteristic change in appearance that coincides with the onset of gene expression. Petesch and Lis (2008) now show that nucleosomes are lost across the entire Hsp70 locus in an initial wave that precedes transcription by RNA polymerase II.
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PMID:Clearing the way for unpaused polymerases. 1861 12

In the fruit fly Drosophila melanogaster, RNA polymerase III transcription was found to be dependent not upon the canonical TATA box-binding protein (TBP) but instead upon the TBP-related factor 1 (TRF1) (Takada, S., Lis, J. T., Zhou, S., and Tjian, R. (2000) Cell 101, 459-469). Here we confirm that transcription of fly tRNA genes requires TRF1. However, we unexpectedly find that U6 snRNA gene promoters are occupied primarily by TBP in cells and that knockdown of TBP, but not TRF1, inhibits U6 transcription in cells. Moreover, U6 transcription in vitro effectively utilizes TBP, whereas TBP cannot substitute for TRF1 to promote tRNA transcription in vitro. Thus, in fruit flies, different classes of RNA polymerase III promoters differentially utilize TBP and TRF1 for the initiation of transcription.
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PMID:Differential utilization of TATA box-binding protein (TBP) and TBP-related factor 1 (TRF1) at different classes of RNA polymerase III promoters. 2395 42