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

Potassium efflux through Ca2+-sensitive K+ channels (K[Ca] channels) is increased in arterial smooth muscle cells from hypertensive rats, but the molecular mechanism is unknown. The goal of this study was to compare the levels of K(Ca) channel current between aortic smooth muscle cells from adult Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) and then use Western blot methods and ribonuclease protection assays to examine the expression and mRNA levels for the K(Ca) channel in these same vascular tissues. Whole-cell patch-clamp methods indicated a larger component of K(Ca) channel current, sensitive to block by iberiotoxin (100 nmol/L), in single aortic smooth muscle cells from SHR compared with WKY. Subsequent Western blot analysis using a site-specific antibody (anti-alpha[913-926]) directed against the S9/S10 linker of the alpha-subunit of the K(Ca), channel revealed a 125-kD immunoreactive band in lanes loaded with either WKY or SHR aortic muscle membranes. The immunoreactive density of this band, which corresponded to the known molecular size of the alpha-subunit, was 2.2-fold greater in lanes loaded with aortic smooth muscle membranes from the hypertensive animals. However, despite this evidence for an increased expression and functional enhancement of K(Ca) channels in aortic smooth muscle membranes of SHR, ribonuclease protection assays with a 32P-labeled riboprobe targeted against the S9/S10 linker of the K(Ca) channel alpha-subunit revealed no difference in mRNA levels for the alpha-subunit between WKY and SHR aortic tissue. These findings provide initial evidence that (1) an increased expression of K(Ca) channels may be a mechanism for the enhanced K(Ca) current in aortic smooth muscle membranes of SHR, and (2) the upregulation of K(Ca) channels in arterial muscle membranes during hypertension, which is regarded as a homeostatic mechanism for buffering vascular excitability, may rely on posttranscriptional events.
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PMID:Increased expression of Ca2+-sensitive K+ channels in aorta of hypertensive rats. 940 60

The non-structural protein NS2 of Bluetongue virus (BTV) is synthesized abundantly in virus-infected cells and has been suggested to be involved in virus replication. The protein, with a high content of charged residues, possesses a strong affinity for single-stranded RNA species but, to date, all studies have failed to identify any specificity in the NS2-RNA interaction. In this report, we have examined, through RNA binding assays using highly purified NS2, the specificity of interaction with different single-stranded RNA (ssRNA) species in the presence of appropriate competitors. The data obtained show that NS2 indeed has a preference for BTV ssRNA over nonspecific RNA species and that NS2 recognizes a specific region within the BTV10 segment S10. The secondary structure of this region was determined and found to be a hairpin-loop with substructures within the loop. Modification-inhibition experiments highlighted two regions within this structure that were protected from ribonuclease cleavage in the presence of NS2. Overall, these data imply that a function of NS2 may be to recruit virus messenger RNAs (that also act as templates for synthesis of genomic RNAs) selectively from other RNA species within the infected cytosol of the cell during virus replication.
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PMID:Sequence specificity in the interaction of Bluetongue virus non-structural protein 2 (NS2) with viral RNA. 1279 83