Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

RNA transcripts starting from the 5' end of the single Mycoplasma pneumoniae rRNA operon were analyzed by several methods. By primer extension analysis a start site was found 62 nucleotides upstream from the start site of the 16S rRNA. This site was preceded by a putative Pribnow box; however, a defined -35 recognition region was absent. The cloned rRNA operon was transcribed in vitro by using purified RNA polymerase of Escherichia coli. A single start site could be demonstrated within a few nucleotides of the start site found by primer extension analysis of M. pneumoniae transcripts. When fragments from the cloned operon were used as hybridization probes, S1 nuclease mapping yielded a single transcript extending approximately 193 nucleotides upstream from the 16S rRNA start site. The region surrounding this endpoint did not resemble any known promoter sequence. Dot blot hybridization of M. pneumoniae RNA to three oligonucleotides consisting of nucleotides -5 to -21, -38 to -54, and -112 to -132 (from the start of the 16S rRNA gene) indicated that most rRNA transcripts were processed at the stem site preceding the 16S rRNA gene. The majority of the longer precursor transcripts, extending beyond this point, did not extend further upstream to an oligonucleotide consisting of nucleotides -112 to -132. It was concluded that transcription of the rRNA operon of M. pneumoniae is initiated by a single promoter. The nucleotide sequence of the region is presented.
...
PMID:Promoter of the Mycoplasma pneumoniae rRNA operon. 283 65

Expression of the melR gene is required for melibiose-dependent stimulation of transcription initiation at the promoter of the melAB operon. Using the S1 nuclease method we have located the melR transcription start point. Transcription from the melR promoter is dependent on cAMP-CRP: specific nucleotide sequences downstream of bp -59 with respect to the melR transcription start are sufficient for full promoter activity. Nucleotide sequence homologies suggest that the cAMP-CRP binding site is located from bp -52 to -31, in exactly the same position as at the galP1 promoter. Using DNase I footprinting we show that cAMP-CRP and RNA polymerase together bind tightly to the melR promoter sequence, creating a strong footprint from bp -70 to +20. Alone, cAMP-CRP binding is hardly detectable, whereas RNA polymerase alone creates a weak footprint centred around the -10 hexamer sequence. When the melR gene is expressed from a cAMP-CRP-independent promoter, melibiose-dependent transcription from the melAB promoter becomes independent of cAMP-CRP, showing that the melR promoter is the primary site of control by cAMP-CRP in the mel regulon.
...
PMID:Transcription from the Escherichia coli melR promoter is dependent on the cyclic AMP receptor protein. 285 97

The genes encoding the major cell wall proteins, middle wall protein and outer wall protein, of Bacillus brevis 47 constitute a cotranscriptional unit (cwp [cell wall protein gene] operon). Primer extension assay of cwp operon transcripts showed the existence of six different 5' ends. This confirmed the results of the previous S1 nuclease protection assay and suggested the existence of several tandemly arranged promoters in the 5' region of the cwp operon. Promoter probe vectors carrying the Bacillus licheniformis alpha-amylase gene were constructed and used for deletion analysis of the 5' region. Three (P1, P2, and P3) of the six suggested promoters were shown to be located within three distinct fragments derived from the 5' region. The -35 and -10 regions of the P1 and P3 promoters resemble the consensus sequence recognized by the sigma-43-type RNA polymerase of Bacillus subtilis. The P2 promoter resembles only the consensus sequence in the -10 region. The P1 and P3 promoters were used to the same extents in Bacillus subtilis as in B. brevis, whereas the P2 promoter was used much less frequently in B. subtilis than in B. brevis. The P2 promoter is used constitutively in B. brevis 47 at all stages of growth, whereas P3 is used only at the exponential phase of growth. P2 could be a promoter of an unknown type that is preferentially used in B. brevis and might be responsible for the constitutive synthesis and secretion of the cell wall proteins into the medium at the stationary phase of growth.
...
PMID:Multiple and tandemly arranged promoters of the cell wall protein gene operon in Bacillus brevis 47. 291 62

We have used partially purified preparations of RNA polymerase II from mock-infected and herpes simplex virus type 1-infected HEp-2 cells to transcribe the herpes simplex virus type 1 strain F BamHI Z DNA fragment containing the promoter for immediate-early RNA-5 (alpha 47), a 1.8-kilobase, spliced RNA. In agreement with the in vivo transcriptional regulation of herpes simplex virus type 1 immediate-early genes, electrophoretic analyses of runoff and truncated transcripts from this template showed that RNA polymerase II from mock-infected cells initiates transcription more selectively than does that from the herpes virus-infected cells at the immediate-early RNA-5 promoter. S1 nuclease mapping of the 5' ends of in vivo- and in vitro-synthesized mRNA placed the initiation site ca. 110 base pairs upstream from the previously published site and also demonstrated the presence of a second, smaller intervening sequence between this new cap site and the previously characterized intervening sequence. S1 analyses also suggested that some splicing of the larger but not the smaller intervening sequence occurred in vitro.
...
PMID:In vitro transcription of herpes simplex virus genes: identification of a new initiation site and second intervening sequence in the immediate-early RNA-5 gene. 298 42

Using supercoiled plasmids containing a (CG)16 sequence downstream of a promoter, it is shown that purified E. coli RNA polymerase can transcribe through the sequence when it is in the B helical form. However, the polymerase together with its nascent transcript is blocked at the boundary of the CG sequence proximal to the promoter when the template is negatively supercoiled to flip the CG sequence to the left-handed Z-form. S1 nuclease mapping of in vivo transcripts from an E. coli gyrase temperature-sensitive mutant harboring the plasmids indicates that the bulk of the transcripts at either permissive or nonpermissive temperatures can proceed through the CG sequence, suggesting that the sequence is normally in the B helical form in vivo. The almost total blockage of transcription in vitro by the (CG)16 sequence in a highly negatively supercoiled DNA is not observed for a d(CA)21 X d(TG)21 insert.
...
PMID:Transcriptional block caused by a negative supercoiling induced structural change in an alternating CG sequence. 298 24

The regulatory region of the Escherichia coli cya gene was analyzed by using S1 nuclease mapping and in vitro transcription experiments. The cya gene was transcribed, both in vivo and in vitro, from one major promoter (P2) and two weak promoters (P1 and P1') that are located about 200 base pairs upstream of P2. The transcription from P2 was specifically inhibited by cAMP-CRP (cAMP receptor protein) in vitro. This regulatory mechanism was shown to be physiologically relevant through quantitative analyses of the cya mRNA in intact cells by S1 and dot blot assays. DNase I protection experiments revealed that cAMP-CRP binds to the cya DNA region between +11 and -20, in which a consensus CRP binding sequence is present. Moreover, it was found that cAMP-CRP alters the binding of RNA polymerase to the promoter region, thus inhibiting the transcription of the cya gene.
...
PMID:Transcription of the Escherichia coli adenylate cyclase gene is negatively regulated by cAMP-cAMP receptor protein. 298 47

The poliovirus RNA-dependent RNA polymerase required an oligouridylate primer or a HeLa cell protein (host factor) to initiate RNA synthesis on poliovirion RNA in vitro. The polymerase synthesized template-sized product RNA in the oligouridylate-primed reaction. In the host factor-dependent reaction, the largest product RNA synthesized by the polymerase was twice the size of the template RNA. About half of the product RNA recovered from this reaction was shown to exist in the form of a snapback sequence. Time-course reactions and pulse-chase experiments showed that the product RNA was only slightly larger than the template RNA at early reaction times and that with time it increased in size to form the dimer-sized product RNA. Inhibition of the elongation reaction by adding only [alpha-32P]UTP and ATP resulted in the formation of template-sized product RNA. The dimer-sized product RNA was unaffected by phenol extraction or proteinase K treatment but was converted to template-sized molecules by S1 nuclease. Dimer-sized poliovirus RNA that was sensitive to S1 nuclease was also isolated from poliovirus-infected cells. The results from this study indicate that the labeled negative-strand product RNA synthesized in vitro was covalently linked to the positive-strand template RNA. Thus, in vitro, the primer-dependent poliovirus RNA polymerase may initiate RNA synthesis in the presence of the host factor by using the 3' end of the template RNA as a primer.
...
PMID:Poliovirus RNA-dependent RNA polymerase and host cell protein synthesize product RNA twice the size of poliovirion RNA in vitro. 298 94

Enhancers are regulatory DNA elements, usually about 200 base pairs (bp) long, which are able to stimulate transcription of linked genes in eukaryotic cells. This activation can be exerted over large distances, and from a position 5' or 3' to the gene. Enhancers have been identified in viral genomes and cellular genes. Using a transient expression assay, we have analysed transcription of the rabbit beta-globin gene and the thymidine kinase gene from herpes simplex virus with and without a simian virus 40 (SV40) enhancer. S1 nuclease mapping shows a high level of specific transcripts when the genes are linked to the enhancer. To determine whether this increased number of transcripts is due to a higher transcription rate, or perhaps to a shift from nonspecific to specific initiation, we have performed run-on transcription assays with isolated nuclei. Our results, presented here, demonstrate that the SV40 enhancer increases the RNA polymerase density within the linked gene. Therefore, enhancers apparently increase the rate of transcription initiation without influencing the specificity of initiation.
...
PMID:Simian virus 40 enhancer increases RNA polymerase density within the linked gene. 298 14

In Escherichia coli some 19 transcription units encoding the 52 ribosomal proteins are scattered throughout the genome. One of the units, the alpha operon, encodes genes for the ribosomal proteins S13, S11, S4 and L17 as well as the alpha subunit of RNA polymerase. We report here the complete 3.0 kb nucleotide sequence of the alpha operon. In addition, we have determined by S1 nuclease mapping the site of transcription termination in this operon.
...
PMID:Nucleotide sequence of the alpha ribosomal protein operon of Escherichia coli. 298 79

Histidine-tRNA synthetase is one of the smallest bacterial aminoacyl-tRNA synthetases. It is less than one-half the size of the largest aminoacyl-tRNA synthetases. The entire nucleotide sequence of the Escherichia coli hisS locus was determined. The coding region is comprised of 424 codons, and the sequence was determined for 200 nucleotides on the 5'- and 3'-sides of the coding region. The translated nucleotide sequence was confirmed extensively by independent amino acid sequence information obtained by Edman degradations of purified peptides and by measurements of peptide masses by fast atom bombardment mass spectrometry. A significant sequence alignment of four bacterial aminoacyl-tRNA synthetases was reported recently (Webster, T., Tsai, H., Kula, M., Mackie, G., and Schimmel, P. (1984) Science 226, 1315-1317). Although the four enzymes vary considerably in length, this match occurs within the first 100 amino acids of each of the four enzymes and is in the segment believed to be part of the catalytic core. But no strong alignment could be found of the histidine sequence with these four tRNA synthetase sequences. This enzyme may be derived, therefore, from a different progenitor. Previous work suggested that three places in the hisS 5'-noncoding sequence could be promoter sites for RNA polymerase (Eisenbeis, S. J., and Parker, J. (1982) Gene 18, 107-114). We detected a 1400-nucleotide RNA species by RNA blot analysis with a hisS-specific probe. S1 nuclease mapping demonstrated a 5'-end to the RNA species occurs at -67 +/- 1, relative to the first nucleotide of the coding region. This position coincides with the predicted start site for transcription from one of the previously proposed promoter sites.
...
PMID:Primary structure of histidine-tRNA synthetase and characterization of hisS transcripts. 299 Dec 72


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---