Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Antibody was raised against purified vaccinia virus RNA polymerase and used to screen a recombinant vaccinia virus-lambda gt11 library. The DNA from several immunopositive clones was shown by Southern hybridization to originate from the vaccinia virus HindIII E fragment. The nucleotide sequence of the RNA polymerase subunit gene predicts a polypeptide 287 amino acids in length and 30,000 daltons in mass. An early transcript with a 5' terminus just upstream of the putative initiation codon was identified by S1 nuclease protection and primer extension analyses, demonstrating that this RNA polymerase subunit is expressed as an early viral gene product. The RNA polymerase subunit was synthesized by a bacterial expression vector to demonstrate that it corresponds to the previously described 37,000-dalton RNA polymerase subunit.
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PMID:Vaccinia virus gene encoding a 30-kilodalton subunit of the viral DNA-dependent RNA polymerase. 221 20

The alpha operon of Escherichia coli contains the genes for ribosomal proteins S13, S11, S4, RNA polymerase subunit alpha, and r-protein L17, in this order. Previous studies have shown that translation of all four ribosomal proteins is regulated by S4, and that binding of S4 to the mRNA at the start site for S13 translation is probably responsible for the regulation of translation of S13, S11 and S4. The alpha gene is "unique" in that it is located between the genes for two ribosomal proteins (S4 and L17) and yet appears to be regulated independently of them. In the present studies, we have measured the synthesis rates of all the alpha operon proteins under a variety of physiological conditions. Our results confirm that alpha gene expression is regulated independently of the co-transcribed ribosomal protein genes and is relatively insensitive to translational feedback repression by S4. S1 nuclease analysis of alpha operon mRNA failed to reveal the presence of any unique transcription start or mRNA cleavage that leads to separation of the alpha cistron from preceding ribosomal protein cistrons. Therefore, it appears that differential regulation of alpha synthesis takes place at the level of mRNA translation. We have also carried out a deletion analysis of the alpha operon leader and identified a region of the alpha operon leader mRNA that is required for regulation by S4. Furthermore, deletion of this region results in increased synthesis of L17 together with S13, S11 and S4, whereas alpha synthesis did not increase significantly. Therefore, we conclude that interaction of S4 with this single target site results in translational repression of not only the proximal three cistrons for S13, S11 and S4 but also that of the last cistron, L17, without affecting the intervening alpha cistron.
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PMID:Regulation of alpha operon gene expression in Escherichia coli. A novel form of translational coupling. 330 51