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

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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)

A protein kinase that phosphorylates Lys(Tyr-Ser-Pro-Thr-Ser-Pro-Ser)4, a synthetic peptide homologous to the evolutionarily-conserved, tandemly-repeated heptapeptide sequence at the C-terminus of the large subunit of eukaryotic RNA polymerase II, has been detected in HeLa cell extracts and chromatographic fractions therefrom. The enzyme, which phosphorylates serine principally, can be distinguished from previously described major protein kinases which phosphorylate the peptide poorly, if at all. It is inhibited by the nucleoside analog, 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole. Results suggest that human placental RNA polymerase II is phosphorylated at the C-terminus of the large subunit by the partially-purified protein kinase and that the phosphorylation is also sensitive to the nucleoside analog.
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PMID:5,6-Dichloro-1-beta-D-ribofuranosylbenzimidazole inhibits a HeLa protein kinase that phosphorylates an RNA polymerase II-derived peptide. 293 May 26

Antisera were raised in rabbits against fusion proteins consisting of beta-galactosidase and partial amino acid sequences of Semliki Forest virus (SFV)-specific non-structural proteins nsP1, nsP2, nsP3 and nsP4. The antisera were specific since each of them precipitated only one labelled protein of a size expected for nsP1, nsP2, nsP3 or nsP4 from lysates of [35S]methionine-labelled SFV-infected BHK-21 cells. The specific antisera also precipitated p220 (with sequences of nsP1, nsP2 and nsP3), p155 (nsP1 and nsP2) and p135 (nsP3 and nsP4) which have been previously shown to be cleavage products of the polyprotein precursor of the non-structural proteins. nsP1, nsP4 and most of nsP3, together with the virus-specific RNA polymerase activity, were in the mitochondrial pellet (P15) fraction of infected BHK-21 cells whereas nsP2 was evenly distributed between P15 and the supernatant fraction (S15). Only antisera directed against nsP3 sequences precipitated a labelled protein from cells incubated with [32P]orthophosphate during SFV infection. Treatment of the immunoprecipitate with calf alkaline intestinal phosphatase reduced the amount of labelled nsP3 considerably. Immunoprecipitated 32P-labelled nsP3, isolated by SDS-PAGE, was subjected to acid hydrolysis. Both phosphoserine and phosphothreonine but not phosphotyrosine could be identified in the hydrolysate. Approximately twice as much [32P]serine as [32P]threonine was detected in nsP3. P15 and S15 fractions were prepared from [35S]methionine- and 32P-labelled SFV-infected cells and the 35S/32P ratio of nsP3 was determined after immunoprecipitation and SDS-PAGE. The nsP3 in S15 was less heavily phosphorylated (about 50%) than P15-associated nsP3. Anti-nsP3 serum revealed large cytoplasmic vesicles in SFV-infected cells in indirect immunofluorescence microscopy.
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PMID:Semliki Forest virus-specific non-structural protein nsP3 is a phosphoprotein. 297 May 23

Purified eukaryotic nuclear RNA polymerase II consists of three subspecies that differ in the apparent molecular masses of their largest subunit, designated IIo, IIa, and IIb for polymerase species IIO, IIA, and IIB, respectively. Subunits IIo, IIa, and IIb are the products of a single gene. We present here the amino acid composition of calf thymus subunits IIa and IIb and the C-terminal amino acid sequence of subunit IIa (IIo) inferred from the nucleotide sequence of part of the mouse gene encoding this RNA polymerase subunit. The calculated amino acid composition of the peptide unique to subunit IIa indicates that subunit IIa contains a domain rich in serine, proline, threonine, and tyrosine. The sequence at the 3' end of the mouse RNA polymerase II largest subunit gene reveals that the C-terminal domain consists of 52 repeats of a seven amino acid block with the consensus sequence Tyr-Ser-Pro-Thr-Ser-Pro-Ser. This sequence is also unusual in that it contains a high percentage of potential phosphorylation sites.
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PMID:A unique structure at the carboxyl terminus of the largest subunit of eukaryotic RNA polymerase II. 299 85

Highly purified African swine fever virus contains a cyclic AMP-independent protein kinase which phosphorylates endogenous virus proteins with a specific activity of about 0.45 pmol/microgram of virus protein. The major substrates for the virion protein kinase in vitro were the structural proteins p10 and p9. Both proteins were phosphorylated preferentially at serine residues. A possible relationship between protein p10 phosphorylation and RNA synthesis in vitro by the virion-associated RNA polymerase is suggested by the finding that N-alpha-tosyl-L-lysyl-chloromethyl ketone inhibited both phosphorylation of p10 and transcription. Two phosphoproteins, with molecular masses of 35 and 17 kDa, were found in African swine fever virus purified from infected Vero cells labeled with [32P]phosphate. A phosphopolypeptide with a molecular mass of about 35 kDa was found in the cytoplasm of infected Vero cells.
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PMID:Phosphorylation of African swine fever virus proteins in vitro and in vivo. 313 81

A bacteriophage gamma Ch4A clone containing a 22-kb rat DNA insert was isolated and found to contain a solitary tRNA(Phe)GAA gene and, 436 bp downstream of it, an Alu-like element. The nucleotide sequence of a 1141-bp DNA fragment containing these genes was determined. The rat tRNA(Phe)GAA gene, with the exception of an additional A in the extra arm, has a sequence identical to that of a rabbit liver tRNA(Phe). The Alu-like element belongs to the rodent B2 family of short interspersed repetitive nucleotide sequences. This repetitive element, B2Phe, is flanked by 12-bp direct repeats, contains an internal split promoter (block A and block B) for RNA polymerase III and is devoid of an A-rich segment at the 3' end. Like other members of the B2 family, the B2Phe element presents 64% sequence homology with rat serine tRNA and contains a serine (GCT) anticodon. Both tRNA(Phe)GAA gene and B2Phe element were found to be transcriptionally active in HeLa cell and Xenopus oocyte nuclear extracts. The tRNA(Phe) gene transcripts were processed during the course of transcription to form mature-size tRNA(Phe). The transcription efficiency of the B2Phe element was found to be an order of magnitude higher than that of the tRNA(Phe) gene. Competition experiments demonstrate that the B2Phe DNA can form a more stable transcription complex than the tRNA(Phe) gene and compete with it for binding of transcription factors.
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PMID:Nucleotide sequence and transcription of a rat tRNA(Phe) gene and a neighboring Alu-like element. 323 68

Purified RNA polymerase II from chicken leukemia cells was found to be an effective substrate for protein kinase C but not cAMP-dependent protein kinase. Protein kinase C catalyzed the incorporation of 1-2 mol of phosphate per mol of polymerase II and the reaction was totally calcium and lipid dependent. Electrophoresis studies revealed a time-dependent increase of phosphate incorporation into RNA polymerase II subunits of 220 KDa, 180 KDa and 150 KDa, with a preferential phosphorylation of the 180 KDa polypeptide. The phosphorylated enzyme has a preference for using single-stranded DNA as the template for transcription, including transcription of the single-stranded myb oncogene sequence. Phosphoamino acid analysis indicated that both serine and threonine residues were phosphorylated at equal amounts. Phosphorylation by protein kinase C increased the affinity of substrate-polymerase binding and the initial rate of RNA synthesis, suggesting a mechanism by which gene expression can be activated by protein kinase C.
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PMID:Protein kinase C phosphorylates leukemia RNA polymerase II. 347 67

Short interspersed repetitive DNA sequences (SINEs) are the major component of dispersed repetitive DNA in all mammalian genomes. Most SINEs contain an intragenic RNA polymerase III promoter that initiates transcription at the 5' end of the repeated DNA sequence and which has been proposed to facilitate the transposition and amplification of these sequences by an RNA-intermediate mechanism. We have discovered several SINE families in the prosimian Galago crassicaudatus which have promoter regions similar to transfer RNA genes. To determine the relationship between Galago SINEs and mammalian tRNA genes, we have compared their sequences. Here, we demonstrate that the Galago monomer and type II SINE families are 68 and 62% homologous, respectively, with a human methionine tRNA gene. We have extended our analysis to include the rat identifier and mouse B2 families and show that their sequences are closely related to alanine and serine tRNA genes, respectively. Our observations suggest that many mammalian SINE families are amplified tRNA pseudogenes.
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PMID:Repeat sequence families derived from mammalian tRNA genes. 385 Nov 63

Transcription of the ribosomal protein genes rplKAJL and of the RNA polymerase genes proBC in the E. coli cells depends on the level of regulatory nucleotide ppGpp. The ppGpp acts as a negative regulator of transcription of the rpoBC genes in conditions of moderate deficiency of amino acids (after the cells were shifted down from amino acid rich to minimal media) or after incomplete deacylation of tRNA exerted by addition of serine-hydroxamate, or by partial inactivation of valyl-tRNA synthetase. Rifampicin of low concentrations, which inhibit total transcription not more than to 50%, stimulates transcription of the genes rpoBC and rplKAJL. It was estimated that stimulatory effect of rifampicin results from the ability of this antibiotic to decrease synthesis of ppGpp--the negative regulator of transcription of genes rplKAJL and rpoBC.
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PMID:[The role of ppGpp in the coordination of transcription of the ribosomal protein genes rplKAJL and RNA-polymerase rpoBC genes in Escherichia coli cells]. 390 13

1. The RNA-dependent RNA polymerase from Halobacterium cutirubrum was purified to electrophoretic homogeneity. 2. It requires a single-stranded molecule of RNA or polyribonucleotide as template. 3. Nearest-neighbour analyses of the products formed on random poly(A,U) or alternating poly(A-U) templates and base analysis of the product of synthesis directed by wheat-germ RNA prove that the template is copied accurately. 4. The enzyme initiates new chains with purine ribonucleoside triphosphates. 5. Sucrose-density-gradient analysis of the product indicates that it has a size distribution similar to that of the template. 6. Preliminary amino acid analysis of the RNA-dependent polymerase shows that it contains much less serine than either of the subunits of H. cutirubrum DNA-dependent RNA polymerase. 7. The RNA-dependent enzyme is unable to substitute for either subunit of the DNA-dependent polymerase, and both the latter are devoid of RNA-dependent activity.
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PMID:Purification and properties of the ribonucleic acid-dependent ribonucleic acid polymerase from Halobacterium cutirubrum. 463 91

Ornithine decarboxylase may undergo posttranslational modifications which alter its function. Both transamidation of glutamine residues in the enzyme catalyzed by TGase and phosphorylation of serine and threonine residues catalyzed by a polyamine-stimulated protein kinase have been demonstrated. Data are presented which suggest that these modifications result in translocation of the modified protein to the nucleolus where it regulates the activity of RNA polymerase I to transcribe rDNA, the only active nucleolar genes. Transamidation of specific proteins with primary amines catalyzed by intracellular TGase may be an important posttranslational modification, capable of altering genetic transcription. The rapid half-life of ODC (10-15 min) may be related to rapid posttranslational modification with loss of enzymatic activity rather than to protein degradation.
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PMID:Ornithine decarboxylase may be a multifunctional protein. 608 23


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