Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Xenopus laevis S-150 cell-free extract catalyzes in vitro transcription of several RNA polymerase III genes. Among these are the Xenopus 5S RNA gene (somatic type) and the Xenopus methionine tRNA gene. In this report we present an analysis of the transcriptional activity of these two genes either in trans-competition experiments or when the genes are co-localized in the same circular plasmid. In the "cis" arrangement, elevated levels of 5S and tRNA gene expression are observed, which are dependent on the relative orientation of the two genes (convergent or in tandem) and the distance between them. The results of these analyses reveal important parameters affecting the expression of juxtaposed genes.
Mol Gen Genet 1990 May
PMID:cis-acting enhancement of RNA polymerase III gene expression in vitro. 238 23

The intergenic spacer of the mouse ribosomal genes contains repetitive 140-base-pair (bp) elements which we show are enhancers for RNA polymerase I transcription analogous to the 60/81-bp repetitive enhancers (enhancers containing a 60-bp and an 81-bp element) previously characterized from Xenopus laevis. In rodent cell transfection assays, the 140-bp repeats stimulated an adjacent mouse polymerase I promoter when located in cis and competed with it when located in trans. Remarkably, in frog oocyte injection assays, the 140-bp repeats enhanced a frog ribosomal gene promoter as strongly as did the homologous 60/81-bp repeats. Mouse 140-bp repeats also competed against frog promoters in trans. The 140-bp repeats bound UBF, a DNA-binding protein we have purified from mouse extracts that is the mouse homolog of polymerase I transcription factors previously isolated from frogs and humans. The DNA-binding properties of UBF are conserved from the mouse to the frog. The same regulatory elements (terminators, gene and spacer promoters, and enhancers) have now been identified in both a mammalian and an amphibian spacer, and they are found in the same relative order. Therefore, this arrangement of elements probably is widespread in nature and has important functional consequences.
Mol Cell Biol 1990 Sep
PMID:Enhancers for RNA polymerase I in mouse ribosomal DNA. 238 26

The major promoter element of the Xenopus laevis 5S RNA gene is located within the transcribed region of the gene and forms the binding site for the transcription initiation factor TFIIIA. We report an analysis of deletion and substitution mutations within the coding region of the major oocyte-type 5S gene of X. laevis. Our results differ from those of previous mutagenesis studies conducted on the somatic-type genes of Xenopus borealis and X. laevis. Transcription assays in whole oocyte S-150 extracts, with both oocyte- and somatic-type mutants, revealed additional promoter elements between the start site for transcription and the binding site for TFIIIA. These sequences regulate the efficiency of binding TFIIIC, a transcription factor required by the genes transcribed by RNA polymerase III containing intragenic promoters. Under TFIIIC-limiting conditions, the somatic-type gene had a 10-fold-higher affinity for TFIIIC than did the major oocyte-type 5S gene. One mutation in the oocyte-type gene (nucleotides +33 to +39) reduced TFIIIC affinity and transcriptional activity four- to fivefold. Differences in TFIIIC affinity between oocyte- and somatic-type genes may contribute to the differential transcription of these genes observed during Xenopus embryogenesis.
Mol Cell Biol 1990 Oct
PMID:Additional intragenic promoter elements of the Xenopus 5S RNA genes upstream from the TFIIIA-binding site. 239 87

The primary structure of three highly repetitive DNA sequences, which are: the most widespread repeats in a number of Hordeum species, represented by 10(5) copies in the genome of Hordeum vulgare, and belong to the BamHI fragment, was studied. The organization of this fragment in the barley genome was described. The computer analysis of the primary structure indicated a great number of inverted repeats (two of them are flanked by short direct repeats) in the BamHI fragment and revealed the short subrepeats of the A, B, C types, five potential RNA-polymerase II sites, one site for RNA polymerase III, open reading frame of 294 b.p. or 210 b.p., sites for polyadenylation and enhancer sequence. The presence of a mobile element (95-568 bp) is very likely in the BamHI fragment, taking into account the location of the mentioned structures along the fragment. This mobile element contains the subrepeats of only A and B types, all sites of transcription initiation, the open reading frame and the inverted repeats on both ends, flanked by the short direct repeats. The transposition mechanisms probably play an essential part in the origin and propagation of the studied BamHI fragment. The presence of potential functional sites in the fragment indicates the possibility of transcription and translation of some highly repetitive Hordeum vulgare DNA.
Mol Biol (Mosk)
PMID:[Genome organization and primary structure of the BamHI fragment of highly repetitive DNA from Hordeum vulgare]. 240 38

The RNA polymerase responsible for the synthesis of coliphage N4 middle RNAs, N4 RNA polymerase II, is composed of two subunits of 30,000 and 40,000 molecular weight. It is the smallest DNA-dependent RNA polymerase characterized to date. We have determined the sequences surrounding the sites of in vivo transcription initiation for this enzyme. Two regions of sequence homology are present: a box at +1, 3' AAAT 5', and a box, 3' TTCTGGAC 5' at a variable distance (16 to 24 base-pairs) upstream from +1. Possible mechanisms for recognition of these sequences are discussed.
J Mol Biol 1990 Jan 20
PMID:N4 RNA polymerase II sites of transcription initiation. 240 52

A base substitution in the 5'-flanking region of a human fetal globin gene is associated with abnormal fetal hemoglobin production. It also reduces by 5- to 10-fold in vitro transcription of the gene by RNA polymerase III. We discuss potential links between polymerase III transcription and abnormal hemoglobin production.
Mol Cell Biol 1986 Sep
PMID:Point mutation associated with hereditary persistence of fetal hemoglobin decreases RNA polymerase III transcription upstream of the affected gamma-globin gene. 243 Dec 98

Cloned human rRNA gene fragments that included the promoter region were introduced into Chinese hamster dihydrofolate reductase-deficient (dhfr-) cells by cotransformation with a dhfr minigene and amplified by selection for methotrexate resistance. The human ribosomal DNA was transcribed by RNA polymerase II, not RNA polymerase I or III. The metaphase chromosome regions containing the transcriptionally active human ribosomal DNA failed to show silver staining.
Mol Cell Biol 1987 Mar
PMID:Human ribosomal DNA fragments amplified in hamster cells are transcribed only by RNA polymerase II and are not silver stained. 243 41

The template-engaged RNA polymerase II was assayed in the nuclei purified from the cerebral hemisphere of 3-, 14- and 30-day old rats. Its activity is the highest at 3-day and declines as development proceeds. Lower transcription at 30-day may either be due to a decrease in the active fraction of chromatin or to a decrease in the amount of RNA polymerase II that is active towards endogenous template, or both. The activity of RNA polymerase I (active in low salt) is also maximal at 3-day and declines as development proceeds. (ADP)ribosylation of chromatin depresses RNA synthesis. This may be due to inactivation of RNA polymerase itself by protein poly(ADP)ribosylation.
Mol Biol Rep 1987
PMID:Effect of in vitro (ADP)ribosylation on transcription of the chromatin of the brain of developing rats. 244 99

An RNA polymerase III transcript, 7SK nuclear RNA, was found to bear sequence homology to the B2 class of highly repeated elements in the mouse genome. Northern blot hybridizations between the small RNAs and two B2 clones showed that only one of them (p49C8) hybridized to 7SK RNA. Both clones, however, hybridized to 4.5SI RNA as well as to a third class of nuclear RNA transcripts around 170 nucleotides long, whose levels were found to be greatly increased upon induction of transformation in a mouse 3T3 cell line transformed with a temperature-sensitive mutant of simian virus 40.
Mol Biol Rep 1987
PMID:Localization of small RNAs hybridizable to a B2 clone in the nuclear fraction of mouse cell lines. 244

Termination of RNA polymerase III transcripts commonly occurs at clusters of T residues. A T4 tract located 72 base-pairs beyond a lysine tRNA gene from Xenopus laevis serves as an efficient termination site for the tRNA(Lys) precursors synthesized from this gene in homologous cell-free extracts. Nucleotides following this T tract influence the extent of read-through transcription in vitro, but in a way that differs from Xenopus 5 S RNA termination. Only approximately 50% of the transcripts initiated in vitro extend as far as this downstream T cluster. The remainder prematurely terminate at a second T4 tract located within the gene itself. The contrasting behaviour of these two T tracts in injected oocytes indicates that termination can be influenced by more than just RNA polymerase III alone, and that different components may contribute to, or hinder, termination at these sites. Prematurely terminated tRNA(Lys) transcripts are detectable in RNA from ovary tissue but not from a kidney cell line, suggesting that read-through transcription beyond intragenic T clusters can be modulated in vivo.
J Mol Biol 1987 Jun 20
PMID:Structure and transcription termination of a lysine tRNA gene from Xenopus laevis. 244 12


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