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)

S1 nuclease mapping of RNA prepared from Pseudomonas amyloderamosa SB-15 suggested that the iam gene coding for isoamylase (glycogen 6-glucanohydrolase [EC 3.2.1.68]) is transcribed from two promoters. The transcription start site for the upstream promoter (termed P1) was located -182 base pairs from the first nucleotide of the initiation codon of iam, whereas the start site for the downstream promoter (termed P2) was 99 base pairs downstream of the P1 start site. Transcriptions from these promoters were induced by maltose and were not repressed by glucose. The promoter regions contained sequences homologous to the consensus sequence recognized by sigma 54 RNA polymerase of enteric bacteria and found in promoters of other Pseudomonas species. Northern (RNA) hybridization provided evidence that the iam gene is transcribed as monocistronic mRNAs with an approximate size of 2.6 kilobases.
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PMID:Transcription of the isoamylase gene (iam) in Pseudomonas amyloderamosa SB-15. 275 57

The td gene contains a 735 bp open reading frame within its 1017 bp intron. A 12 nucleotide stretch may form a stable secondary structure with the putative Shine-Dalgarno sequence of the intron open reading frame and thus impair its translation. SP6 RNA polymerase transcripts of the td gene synthesized in vitro at 40 degrees C encompass a 2.7 kb primary transcript, a 1.7 kb mRNA, and a 1 kb intron RNA. The excised intron RNA consisted of linear and cyclized forms. RNAase H studies and resistance of the cyclized intron to linearization by HeLa cell debranching enzyme suggest it to be circular. Self-splicing of isolated td primary transcript occurred only marginally at 28 degrees C, but increased progressively to 50 degrees C, and required the presence of both Mg++ and a guanosine cofactor. An internal guide sequence is evident which may align the 5' splice site with the 3' end, presumably for precise exon ligation.
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PMID:Characterization of the intron in the phage T4 thymidylate synthase gene and evidence for its self-excision from the primary transcript. 369 96

Bacterial reverse transcriptase (RT) is responsible for synthesis of multicopy single-stranded DNA (msDNA) consisting of single-stranded DNA linked to an internal guanosine residue of RNA by an unusual 2',5'-phosphodiester linkage. Here we purified a bacterial RT to homogeneity from Escherichia coli harboring the RT gene from retron-Ec73. The purified RT-Ec73 was able to synthesize msDNA in a cell-free system using an RNA template produced in vitro by T7 RNA polymerase. The in vitro synthesized msDNA was released from the template RNA only when treated with yeast debranching enzyme DBR1, a specific nuclease for a 2',5'-phosphodiester linkage. The position of the branching G residue in the template RNA and the DNA sequence of the cell-free product were identical to those of msDNA-Ec73 synthesized in vivo. These results clearly demonstrate that the formation of the 2',5'-phosphodiester linkage in msDNA synthesis is carried out by RT itself.
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PMID:The formation of the 2',5'-phosphodiester linkage in the cDNA priming reaction by bacterial reverse transcriptase in a cell-free system. 752 62

A boy with failure to thrive and isolated pancreatic amylase deficiency is described. Immunoprecipitation confirmed only salivary isoamylase in duodenal fluid at ages 20 and 33 months. Because normal pancreatic amylase messenger RNA was detected by reverse-transcriptase polymerase chain reaction in the fluid, failure of the normal maturation of pancreatic amylase secretion may explain the deficiency.
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PMID:Isolated pancreatic amylase deficiency: probable error in maturation. 1083 89

Noncoding circular RNAs are widespread in the tree of life. Particularly, intron-containing circular RNAs which apparently upregulate their parental gene expression. Entamoeba histolytica, the causative agent of dysentery and liver abscesses in humans, codes for several noncoding RNAs, including circular ribosomal RNAs, but no intron containing circular RNAs have been described to date. Divergent RT-PCR and diverse molecular approaches, allowed us to detect bona fide full-length intronic circular RNA (flicRNA) molecules. Self-splicing reactions, RNA polymerase II inhibition with Actinomycin D, and second step of splicing-inhibition with boric acid showed that the production of flicRX13 (one of the flicRNAs found in this work, and our test model) depends on mRNA synthesis and pre-mRNA processing instead of self-splicing. To explore the cues and factors involved in flicRX13 biogenesis in vivo, splicing assays were carried out in amoeba transformants where splicing factors and Dbr1 (intron lariat debranching enzyme 1) were silenced or overexpressed, or where Rabx13 wild-type and mutant 5'ss (splice site) and branch site minigene constructs were overexpressed. Whereas SF1 (splicing factor 1) is not involved, the U2 auxiliary splicing factor, Dbr1, and the GU-rich 5'ss are involved in postsplicing flicRX13 biogenesis, probably by Dbr1 stalling, in a similar fashion to the formation of ciRNAs (circular intronic RNAs), but with distinctive 5'-3'ss ligation points. Different from the reported functions of ciRNAs, the 5'ss GU-rich element of flicRX13 possibly interacts with transcription machinery to silence its own gene in cis. Furthermore, introns of E. histolytica virulence-related genes are also processed as flicRNAs.
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PMID:Postsplicing-Derived Full-Length Intron Circles in the Protozoan Parasite Entamoeba histolytica. 3012 75