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

We have performed a systematic structure-function analysis of Saccharomyces cerevisiae TAF25, an evolutionarily conserved, single-copy essential gene which encodes the 206-amino-acid TAF25p protein. TAF25p is an integral subunit of both the 15-subunit general transcription factor TFIID and the multisubunit, chromatin-acetylating transcriptional coactivator SAGA. We used hydroxylamine mutagenesis, targeted deletion, alanine-scanning mutagenesis, high-copy suppression methods, and two-hybrid screening to dissect TAF25. Temperature-sensitive mutant strains generated were used for coimmunoprecipitation and transcription analyses to define the in vivo functions of TAF25p. The results of these analyses show that TAF25p is comprised of multiple mutable elements which contribute importantly to RNA polymerase II-mediated mRNA gene transcription.
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PMID:Molecular genetic dissection of TAF25, an essential yeast gene encoding a subunit shared by TFIID and SAGA multiprotein transcription factors. 1153 54

Photoanlogues of the initiation substrates of the RNA polymerase II, N3ArNH(CH2)(n)NHpppA where N3Ar is 5-azido-2-nitrobenzoyl group (n = 2 or 4) were synthesized, allowing the preparation of photoreactive oligonucleotides in situ by RNA polymerase II for application as photolabels. Photolysis of p-nitro-substituted aromatic azide in aqueous medium was investigated. Using the azoxy-coupling reaction it was possible to determine whether a nitrene or p-nitrophenyl hydroxylamine azoxy compound is the trappable intermediate that is generated at ambient temperature in aqueous solution.
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PMID:Photoanalogues of the initiation substrates of the RNA polymerase II, 5-azido-2-nitrobenzoyl derivatives of the ATP gamma-amidophosphate: the possible photoinduced degradation of the functional group to an N-arylhydroxylamine. 1556 82

An activator protein, Alt, synthesized during the early state of lytic infection is required for transcription of the late operon in the lactococcal phage TP901-1. In order to identify amino acid residues in the Alt protein required for activation of the TP901-1 late promoter, P(late), hydroxylamine mutagenesis was performed, resulting in almost saturating mutagenesis of alt. Twenty-three different non-functional alt alleles containing one, and in one case two amino acid exchanges were isolated and analyzed. Eight of the twenty-three mutant proteins were still able to activate the P(late) promoter to some extent. Our results show that alt encodes a protein of 16.7 kDa and that the last fourteen amino acids in the C-terminal part of the protein are required for activation of the P(late) promoter. By combining sequence analysis with experimental data we suggest that the C-terminal half of the Alt protein contains a helix-turn-helix-like motif involved in DNA binding. We also propose that the C-terminal half of the Alt protein may be involved in interactions with the bacterial RNA polymerase, whereas the N-terminal half of the protein is proposed to be important for the overall protein structure.
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PMID:Mutational analysis of the activator of late transcription, Alt, in the lactococcal bacteriophage TP901-1. 1706 50

Treatment of poly C with methoxyamine leads to formation of 5,6-dihydro-6-methoxyaminocytosine residues in the polymer. These direct incorporation of adenylate residues into the poly G synthesized when the modified poly C is used as a template for RNA polymerase. The process is analogous to that of hydroxylamine-induced errors in replication. Comparison of the uptake of [14C]methoxyamine by the poly C with the percentage of adenylate incorporated in the poly G shows that the induction of errors is a highly efficient process: every modified cytosine residue directs the incorporation of one adenylate residue. A probable explanation for this is that the incorporation is mediated by hydrogen-bonding between the adenine and a predominant imino tautomer of the cytosine adduct.
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PMID:The efficiency of induction of mutations by hydroxylamine. 1976 59


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