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)

Omega is a small protein found associated with Escherichia coli RNA polymerase. The role of omega, if any, in transcription is not known. We have cloned the omega-encoding gene (rpoZ) so that we can produce large amounts of omega by over-production and to introduce mutations in its gene. We determined the N-terminal amino acid (aa) sequence of omega by aa microsequencing. Using the sequence we synthesized an eight-fold ambiguous 14-mer oligodeoxynucleotide probe and screened an E. coli genomic library using the base composition independent method of hybridization reported by Wood et al. [Proc. Natl. Acad. Sci. USA 82 (1985) 1585-1588]. With this method we isolated a clone that contained part of rpoZ which we used as a probe to isolate the complete gene. The sequence of the region containing the rpoZ gene predicts a highly charged protein of 91 aa with an Mr of 10 105. In addition, upstream from the gene is a good promoter-like sequence. We have verified by S1 mapping that in vivo transcripts originate from this promoter and possibly from a second promoter farther upstream.
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PMID:The cloning and sequence of the gene encoding the omega subunit of Escherichia coli RNA polymerase. 354 61

The temperature-sensitive BN51 cell cycle mutant of BHK cells arrests in G1 at the nonpermissive temperature (39.5 degrees C). We have previously reported cloning the gene which complements this mutation. The complementing gene encodes a highly charged protein with a basic amino-terminal domain and an acidic carboxyl-terminal domain. We have recently found that the predicted BN51 protein shows significant homology to the 53 kilodalton subunit of RNA polymerase C (III) from Saccharomyces cerevisiae. Consistent with this, antibodies raised to fusion proteins containing BN51 coding sequences and antipeptide antibodies reveal that the BN51 gene encodes a 48 kilodalton protein which appears to be located primarily in the nucleus following subcellular fractionation and by immunohistochemistry. Analysis of RNA polymerase III activity in temperature-sensitive BN51 cells by nuclear runoff transcription assay reveals a marked drop in RNA polymerase III transcription after 48 h at the nonpermissive temperature (39.5 degrees C). This is correlated with a significant decrease in low molecular weight RNAs after 48 h at 39.5 degrees C. In addition, RNA polymerase III activity in S100 extracts of BN51 cells is more sensitive to heat inactivation at 39 degrees C than control extracts from BHK cells. When the yeast gene is introduced into the BN51 cells in a mammalian expression vector, it weakly complements the BN51 mutation in that it prevents cell death at 39.5 degrees C. The mechanism by which inhibition of RNA polymerase III activity leads to arrest in G1 is unclear but is not due to a marked decrease in total protein synthesis.
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PMID:The gene complementing a temperature-sensitive cell cycle mutant of BHK cells is the human homologue of the yeast RPC53 gene, which encodes a subunit of RNA polymerase C (III). 837 34

Regulated transcription initiation requires, in addition to RNA polymerase II and the general transcription factors, accessory factors termed mediators or adapters. We have used affinity chromatography to identify a collection of factors that associate with Saccharomyces cerevisiae RNA polymerase II (P. A. Wade, W. Werel, R. C. Fentzke, N. E. Thompson, J. F. Leykam, R. R. Burgess, J. A. Jaehning, and Z. F. Burton, submitted for publication). Here we report identification and characterization of a gene encoding one of these factors, PAF1 (for RNA polymerase-associated factor 1). PAF1 encodes a novel, highly charged protein of 445 amino acids. Disruption of PAF1 in S. cerevisiae leads to pleiotropic phenotypic traits, including slow growth, temperature sensitivity, and abnormal cell morphology. Consistent with a possible role in transcription, Paf1p is localized to the nucleus. By comparing the abundances of many yeast transcripts in isogenic wild-type and paf1 mutant strains, we have identified genes whose expression is affected by PAF1. In particular, disruption of PAF1 decreases the induction of the galactose-regulated genes three- to fivefold. In contrast, the transcript level of MAK16, an essential gene involved in cell cycle regulation, is greatly increased in the paf1 mutant strain. Paf1p may therefore be required for both positive and negative regulation of subsets of yeast genes. Like Paf1p, the GAL11 gene product is found associated with RNA polymerase II and is required for regulated expression of many yeast genes including those controlled by galactose. We have found that a gal11 paf1 double mutant has a much more severe growth defect than either of the single mutants, indicating that these two proteins may function in parallel pathways to communicate signals from regulatory factors to RNA polymerase II.
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PMID:Paf1p, an RNA polymerase II-associated factor in Saccharomyces cerevisiae, may have both positive and negative roles in transcription. 855 95

Cajal bodies are nuclear structures that are involved in biogenesis of snRNPs and snoRNPs, maintenance of telomeres and processing of histone mRNA. Recently, the SUMO isopeptidase USPL1 was identified as a component of Cajal bodies that is essential for cellular growth and Cajal body integrity. However, a cellular function for USPL1 is so far unknown. Here, we use RNAi-mediated knockdown in human cells in combination with biochemical and fluorescence microscopy approaches to investigate the function of USPL1 and its link to Cajal bodies. We demonstrate that levels of snRNAs transcribed by RNA polymerase (RNAP) II are reduced upon knockdown of USPL1 and that downstream processes such as snRNP assembly and pre-mRNA splicing are compromised. Importantly, we find that USPL1 associates directly with U snRNA loci and that it interacts and colocalises with components of the Little Elongation Complex, which is involved in RNAPII-mediated snRNA transcription. Thus, our data indicate that USPL1 plays a key role in RNAPII-mediated snRNA transcription.
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PMID:A role for the Cajal-body-associated SUMO isopeptidase USPL1 in snRNA transcription mediated by RNA polymerase II. 2441 72