Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.3 (RNase III)
 1,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The procaryotic RNA processing enzyme RNase III (endoribonuclease III [EC 3.1.4.24]) was used to probe vesicular stomatitis virus (VSV) RNAs for specific sites that could be recognized and cleaved. The effect of the enzyme on the RNAs was monitored by measuring their subsequent migration in denaturing agarose-urea gels. VSV virion RNA (negative strand; Mr, 4 X 10(6)) was cleaved by the enzyme to yield a set of discrete fragments which ranged on size from 3.5 X 10(6) to 0.2 X 10(6) daltons. The cleavage was a function of enzyme concentration, salt concentration, and time. A maximum of 20 to 22 fragments was generated under conditions of low enzyme concentration or short times of incubation. VSV genome-length intracellular RNA of both + and - polarity was also cleaved by RNase III. In contrast to the findings with virion-length RNA, however, the migration rates of VSV mRNA's purified by chromatography on polyuridylic acid-Sepharose were unaffected by treatment with RNase III. These results show that specific sites in the virion RNA and its full-length complement can be recognized by RNase III. Sites of this type are not present in the polyadenylic acid-containing mRNA, however.
 ...
PMID:RNase III cleaves vesicular stomatitis virus genome-length RNAs but fails to cleave viral mRNA's. 22 9

[3H]Uracil-pulse-labeled RNA from Escherichia coli infected with f1 bacteriophage was fractionated on polyacrylamide gels containing urea. Eight phage-specific RNA species were present with approximate lengths ranging from 2100 to 400 nucleotides. The amount of the seven largest species was increased when the infected bacteria were incubated at 41 degrees C. When the RNA was isolated and used as message in an in vitro protein-synthesizing system, most of the RNA species appeared to direct the synthesis of the phage gene VIII protein. The six largest species also directed the synthesis of the phage gene V protein. Some of the labeled smaller RNA species increased in amount after addition to rifampicin, suggesting that they may have resulted from cleavage of larger RNA species. These particular smaller RNA species also were present in infected bacteria containing a mutant RNase III. The data are discussed in terms of the regulation of synthesis of the phage-specific proteins.
 ...
PMID:Bacteriophage f1 infection of Escherichia coli: identification and possible processing of f1-specific mRNAs in vivo. 37 28

Irradiation with ultraviolet light was used to create two nonlinear RNA molecules. Circular potato spindle tuber viroid (PSTV) RNA was crosslinked at a single site to generate a figure eight-shaped molecule; 5S rRNA from HeLa cells was transformed into an alpha-shaped molecule with a small circular element and two arms (1). Crosslinked RNA's could be separated from their untreated counterparts by electrophoresis in polyacrylamide gels containing urea. The gel mobility of crosslinked PSTV was not altered by boiling, treatment with E. coli RNase III or glyoxalation. However, mild nuclease digestion ("nicking") produced derivatives which migrated more slowly than the starting material in gels of certain polyacrylamide concentrations, but not in others. Limited nuclease digestion of crosslinked 5S rRNA did not generate any detectable products with reduced mobility in the gels tested. Thus, the ability of the "nicking assay" to reveal circular elements within nonlinear RNA's can vary depending upon the composition of the gel chosen for analysis and on the size of the circular element relative to the rest of the molecule.
 ...
PMID:Unusual properties of two branched RNA's with circular and linear components. 241 Aug 57

Three ribonucleases, RNase I, RNase II and RNase III, were purified from the 109,000 X g supernate of detergent-treated Tetrahymena pyriformis strain W. RNases I and II act optimally at pH 5.5-6.0 and are inhibited by increasing concentrations of salts of monovalent cations. RNase III acts optimally at pH 7.5 and is activated 1.5-fold by millimolar concentrations of ZnSO4 and 5-fold by 50 mM KCl. RNases II and III are activated approximately 100% in the presence of 3 M and 5 M urea respectively. All enzymes are heat-sensitive and acid-resistant. They are endonucleases forming 2',3'-cyclic products. Their base specificity, as tested against ribosomal RNAs of known sequence, is as follows: RNase I hydrolyzes preferentially YpN and secondarily GpN bonds, RNase II is highly specific for RpN bonds, though the preparation can also hydrolyze the UpU sequence. Finally the principal targets of RNase III are YpR sequences and secondarily YpY sequences. A shorthand visualization of base specificity of nucleases in the form of right isosceles triangles is presented. The triangles are constructed by subdividing each of the two perpendicular sides in as many units as the maximum number of times the most abundant dinucleotide appears in all substrates employed and plotting the frequency of hydrolysis of each dinucleotide sequence by the enzyme under study. The proximity of each dinucleotide sequence to the hypotenuse or to one of the perpendicular sides is indicative of its susceptibility or resistance to the enzyme's action.
 ...
PMID:Specificity and other properties of three ribonucleases of Tetrahymena pyriformis. 311 47

Bacteriophage lambda transcripts were synthesized in vitro using lambda b2 DNA and Escherichia coli RNA polymerase. RNA molecules initiating with ATP were labeled exclusively at the 5'-end by transcribing in the presence of [gamma-32P]ATP. They were analyzed by electrophoresis in 3.5% polyacrylamide, 7.5 M urea gels followed by autoradiography. The previously known 6 S rho-independent transcript and rho-dependent 9 S and 8 S transcripts were observed. A new rho-dependent 5 S transcript was also detected. The 5 S RNA was not the result of cleavage of larger RNAs by ribonuclease III. Analysis of partial ribonuclease T1 digestion products of isolated 5'-end-labeled transcripts showed that the 5 S RNA is synthesized from promoter pR, the promoter for the 9 S and 8 S RNA species. A similar analysis of transcripts labeled with 32P exclusively at the 3'-terminus by the post-transcriptional addition of a [32P]pCp moiety with T4 RNA ligase revealed the positions of guanosine nucleotides proximal to the 3'-hydroxyl end. This information, and inspection of the known DNA nucleotide sequence downstream from pr, allowed us to conclude that the 5 S RNA is a mixture of molecules 112 and 113 nucleotides long terminating in the middle of gene cro. The nucleotide sequence at the 3'-end of the 5 S RNA is similar to that of other rho-dependent transcripts and lacks the oligo(U) found at the terminus of rho-independent transcripts.
 ...
PMID:Characterization of a rho-dependent termination site within the cro gene of bacteriophage lambda. 644 59

Unfolding by chemical denaturants and the linear extrapolation method are widely used to determine the free energy of proteins. Ribonuclease 3 from bullfrog shows an extraordinary behavior in guanidinium hydrochloride in comparison to its homologues ribonuclease A and onconase with a high transition midpoint of denaturation but an apparently low cooperativity. The analysis of the interdependence of thermal, urea-, and guanidine hydrochloride-induced unfolding revealed that whereas addition of urea resulted in the expected destabilization of all three proteins, guanidine hydrochloride acted diversely: in contrast to ribonuclease A and onconase, both of which were destabilized as expected, low concentrations of guanidine hydrochloride significantly stabilize ribonuclease 3 from bullfrog. This stabilizing effect was endorsed by in silico docking studies.
 ...
PMID:Striking stabilization of Rana catesbeiana ribonuclease 3 by guanidine hydrochloride. 2339 13