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)

Virions of Newcastle disease virus (NDV) were disrupted with Triton X-100 in the presence of high salt and nucleocapsids were isolated by ultracentrifugation. The nucleocapsids had very low transcriptase activity and contained only NP as a prominent protein constituent, the bulk of L and P proteins not being retained. The L and P proteins were isolated by sequential treatment of the virions with low- and high-salt detergent followed twice by successive chromatography on phosphocellulose column and examined for their effect on RNA synthesis in a standard transcriptase system using the nucleocapsids as template. When both L and P proteins were added to the template, the RNA synthetic activity was greatly stimulated. P protein alone could not enhance but rather suppressed the activity. L protein exhibited stimulation to some extent but due to residual small amount of P protein in both L protein fraction and the template it has not been elucidated whether L protein could function as a polymerase by itself. These results indicate that both L and P proteins are required to reconstitute a fully active transcriptive complex with a functional template. Attempts have been made to isolate intracellular transcriptive complex from NDV-infected MDBK cells and to determine the protein species involved. The active complex has been recovered neither from cytoplasmic extract obtained by hypotonic disruption nor from Triton X-100 soluble fraction of the cells. However, we could isolate the complex from an extract by double detergents (Tween 40 and deoxycholate) solubilization. The complex contained L, P, and NP as virus specific proteins and several cellular proteins. These results support the concept that both L and P proteins are required for NDV-RNA synthesis and suggest further that the intracellular transcriptive complex may be associated with some cellular structure resistant to Triton X-100 but sensitive to the double detergents, presumably cytoskeletal frame work.
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PMID:Transcriptive complex of Newcastle disease virus. I. Both L and P proteins are required to constitute an active complex. 668 7

Five hundred putative RNA polymerase mutants of Bacillus subtilis were isolated by selecting for resistance to the RNA polymerase inhibitors rifampin (Rifr), streptovaricin (Strr) or streptolydigan (Stdr). This collection was screened for mutants that were unable to sporulate at the non-permissive temperature of 46 degrees C, yet which sporulated well at 37 degrees C and had normal vegetative growth (Spots phenotype). Nearly one half of the Rifr and one quarter of the Stvr mutants were Spots, whereas none of the Stdr mutants had this phenotype. The streptovaricin resistant strain stv84 was studied in detail. The stv84 mutation maps between cysA14 and strA39 on the B. subtilis chromosome, and the Stvr and Spots phenotypes cotransform at a frequency of 100%. The Spots phenotype of stv84 could be physiologically corrected by supplementing the growth medium with inhibitors of RNA synthesis such as rifampin or azauracil, with carbohydrates such as ribose, mannose or glycerol, or with lipids such as Tween 40 or fatty acids native to Bacillus subtilis membranes. A Spots phenotype resembling that of stv84 was produced in wild type B. subtilis by adding cerulenin, an inhibitor of fatty acid biosynthesis, to the growth medium. This cerulenin-induced sporulation defect was reversed by the same treatments that correct the temperature-sensitive genetic defect of stv84. These data indicate that the Spots phenotype of strain stv84 is not due to an intrinsic inability of the mutant RNA polymerase to transcribe developmentally-specific genes at the nonpermissive temperature. Rather, the data suggest that the stv84 lesion causes a physiological imbalance which disrupts membrane structure or function in sporulating cells.
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PMID:Physiological suppression of the temperature-sensitive sporulation defect in a Bacillus subtilis RNA polymerase mutant. 680 29

The temperature-sensitive sporulation phenotype (Spots) of Bacillus subtilis RNA polymerase, ribosomal and protein synthesis elongation factor G mutations can be corrected by supplementing the growth medium with carbohydrates such as ribose or glycerol, or with synthetic lipids such as Tween 40. The data suggest that these mutations affect a single common aspect of developmental cell function. It is proposed that these lesions prevent sporulation by disturbing the regulation of sporulating cell metabolic balance.
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PMID:Physiological suppression of Bacillus subtilis conditioned sporulation phenotypes: RNA polymerase and ribosomal mutations. 680 30