Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.4 (ribonuclease)
 6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Infusion of 125I-(Tyr A14)-insulin at tracer doses into the cerebrospinal fluid (CSF) resulted in a slow rate of increase in the CSF-labeled insulin during the first 2 hours with a plateau thereafter. Labeled insulin was cleared from the CSF at a higher rate than 3H-inulin, a marker of CSF bulk flow. The labeled insulin was mainly distributed in all the ventricular and periventricular brain regions. Small amounts of degraded insulin appeared in the CSF. Coinfusion with an excess of unlabeled insulin impaired the clearance and degradation of labeled insulin. It also inhibited the labeling in medial hypothalamus, olfactory bulbs and brain stem. In contrast, coinfusion of ribonuclease B (used to test the specificity of uptake) was without any effect. It was concluded that there is an active insulin intake from CSF into brain specific compartments that is presumably essential for the effects of insulin on brain function.
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PMID:Metabolic clearance of insulin from the cerebrospinal fluid in the anesthetized rat. 218 32

A method is described for using the cross-linking reagent 4'-(hydroxy-methyl)-4,5',8-trimethylpsoralen (HMT) to map base paired regions and higher-order structure within RNA molecules. Applying this method to yeast tRNAPhe, we have specifically identified cross-links within the acceptor stem between U6 X U68, in the D-stem between C11 X C25, and in the T psi-stem between U50 X C63 and U52 X C63. We have also identified a unique cross-link between U8 X C48 which are trans pyrimidines in the core region due to tertiary interactions between U8:A14 and C48:G15. The precise point of cross-linking was deduced in every case by using purine-specific U2 ribonuclease along with cytidine-specific CL3 ribonuclease which will anomalously cleave after photoreversed pyrimidines. The ability to map the precise point of cross-linking should prove invaluable in identifying nucleotides in close proximity within the tertiary structure of other RNA molecules.
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PMID:Mapping of psoralen cross-linked nucleotides in RNA. 642 2

It was suggested in an accompanying paper [Taliansky et al. (1982b), Virology, 117, 000-000] that two reconstitution initiation sites (RIS I and RIS II) were functionally active in RNA of the temperature-sensitive (ts) TMV mutant Ni2519 upon reassembly at a nonpermissive temperature; initiation of reassembly that started at two sites on the Ni2519 RNA molecule resulted in defective (ribonuclease-sensitive) virus particle (DVP) formation. RIS(s) was(were) defined as a segment(s) of Ni2519 RNA protected from the action of ribonuclease T1 by the coat protein within an incomplete nucleoprotein complex (I-NPC) formed upon limited TMV reassembly at nonpermissive (33 degrees and permissive (24 degrees) temperatures. Tl-resistant oligonucleotides protected within I-NPC were finger-printed, sequenced, and assigned to specific regions on the Ni2519 RNA molecule. It was shown that only RIS I was operative on Ni2519 RNA at 24 degrees as well as on A14 (a temperature-resistant strain, the wild type for Ni2519) RNA at both 24 and 33 degrees ; RIS I corresponded to the so-called Oa (origin of assembly) of a common TMV strain previously studied and was located at a distance of about 800 nucleotides from the 3'-end of the RNA molecule. In contrast, two RISs were revealed on Ni2519 RNA assembled at 33 degrees ; of the two RISs operative in this case the first one is identified as RIS I, while the second (RIS II) is located within 300-520 nucleotides from the 3'-end, i.e., within the coat protein gene. The latter corresponds to the so-called SERF (specifically encapsidated RNA fragment) of the RNA of common TMV.
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PMID:A study of TMV ts mutant Ni2519. III. Location of the reconstitution initiation sites on Ni2519 RNA. 1863 36