Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The organization of select proteins within ribonucleoprotein particles containing heterogeneous nuclear and uridine-rich small nuclear RNAs (hnRNP and UsnRNP respectively) was examined by chemical cross-linking and ribonuclease digestion using diagonal two dimensional PAGE and immunoblotting detection systems. Monoclonal antibodies specific for A2, C1 and C2 hnRNP proteins, detected these proteins at gel coordinates which suggested homotypic dimers and trimers of A2 and homotypic trimers, hexamers and larger multimers of C1 and C2. Ribonuclease digestion did not alter the cross-linking properties of hnRNP C1 and C2 proteins but did result in loss of A2 homotypic dimers and trimers. Blots simultaneously reacted with hnRNP specific monoclonal antibodies and autoimmune patient serum (RNP/Sm), or monoclonal antibodies reactive with the U1 snRNP specific 63 kDa protein and/or the UsnRNP common proteins B', B and D revealed no complexes which would indicate interactions between hnRNPs and UsnRNPs. The U1 UsnRNP specific 63 kDa protein appeared not to be cross-linked to UsnRNP common B', B and D proteins. The data also suggested that UsnRNP common protein D was cross-linkable to UsnRNP common proteins D', E and G but not to B' and B. The cross-linking properties of D were unaffected by ribonuclease digestion. In contrast, ribonuclease digestion resulted in an inability to cross-link select complexes containing either B' and B, or p63. The data suggest that both hnRNPs and UsnRNPs are comprised of RNA-dependent and RNA-independent protein-protein interactions.
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PMID:Reversible chemical cross-linking and ribonuclease digestion analysis of the organization of proteins in ribonucleoprotein particles. 323 Dec 14

A soluble RNA-dependent RNA polymerase was purified from the cytoplasm of poliovirus-infected HeLa cells. A single virus-specific protein designated as p63 (or NCVP4) copurified with this activity. The purified polymerase was free of ribonuclease activity and was shown to copy poliovirion RNA when oligo(U) was added to the in vitro reaction mixture. Characterization of the product RNA by electrophoresis in methylmercury (II) hydroxide-agarose gels showed that genome-sized copies of poliovirion RNA were synthesized in vitro by the purified polymerase. The product RNA was shown to be heteropolymeric, complementary to virion RNA, and covalently linked to oligo(U). The product RNA contained the expected distribution of UMP and GMP containing dinucleotide pairs which included a very low frequency of CpG pairs. The amount, size distribution, and rate of synthesis of product RNA was very dependent on the in vitro reaction conditions. Full sized product RNA was synthesized in about 6 min when reaction conditions were used that yielded maximum elongation rates (pH 8.0, 7 mM Mg2+, 37 degrees C). Under these conditions, most of the product RNA recovered from a 1-h reaction was full sized. Thus, the polymerase was found to specifically initiate synthesis at the 3'-end of the template using an oligo(U) primer and to carry out an elongation reaction at about 1250 nucleotides/min that resulted in the synthesis of full sized product RNA.
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PMID:Genome-length copies of poliovirion RNA are synthesized in vitro by the poliovirus RNA-dependent RNA polymerase. 627 40

Recently, the p53 homolog p63 has been implicated in sustaining the epidermal stem cell population. The p63 gene encodes six major products with transactivating or dominant-negative properties. The expression pattern of these isoforms in keratinocytes was investigated here. Northern blot, ribonuclease protection assay, reverse transcription-polymerase chain reaction, and western blot techniques sensitive for all six p63 isotypes verified the predominant expression of the truncated and potentially dominant-negative isotype DeltaNp63alpha in human keratinocytes. The expression of this isoform is downregulated when proliferating human primary keratinocytes begin to differentiate after growth factor withdrawal. The onset of differentiation does not change the ratio of two other weakly expressed isotypes DeltaNp63gamma and TAp63alpha relative to DeltaNp63alpha. Treatment of primary human keratinocytes with all-trans retinoic acid does not alter the expression pattern of p63 isotypes but prevents its downregulation as observed in control cell cultures. These data suggest that p63 expression in human keratinocytes is affected by all-trans retinoic acid and this influence might contribute to the fine tuned keratinocyte proliferation and differentiation equilibrium in the mammalian epidermis.
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PMID:Retinoic acid inhibits downregulation of DeltaNp63alpha expression during terminal differentiation of human primary keratinocytes. 1185 86