Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We earlier isolated a cDNA clone (NGR1) encoding a wound-inducible ribonuclease (RNase NW) from leaves of Nicotiana glutinosa [Kariu et al. Biosci. Biotechnol. Biochem., 62, 1144-1151 (1998)]. In this study, two distinct cDNA clones, NGR2 and NGR3, encoding proteins with a ribonuclease-related sequence in the N. glutinosa leaves, were amplified and sequenced. The nucleotide sequences of NGR2 and NGR3 consist of 1244 bp and 1069 bp, and have open reading frames encoding 277 (RNase NGR2) and 236 (RNase NGR3) amino acid residues, respectively. The deduced amino acid sequences of the putative RNases NGR2 and NGR3 showed 33% and 58% amino acid sequence identity, respectively, with that of RNase NW and 32% identity with each other. Sequence comparison showed that NGR2 is similar to RNase RNS2 (61%) from Arabidopsis thaliana, while NGR3 is related to RNase LX (84%) from tomato (Lycopersicon esculentum). RNA gel blot analysis showed that the RNase NGR2 gene is constitutively expressed to measurable levels; it is not increased by either wounding or TMV infection. In contrast, the expression of the NGR3 gene is induced after 48 h upon TMV infection.
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PMID:Molecular cloning of cDNAs encoding ribonuclease-related proteins in Nicotiana glutinosa leaves, as induced in response to wounding or to TMV-infection. 1199 14

We previously isolated from Nicotiana glutinosa leaves three distinct cDNA clones, NGR1, NGR2, and NGR3, encoding a wound-inducible RNase NW, and putative RNases NGR2 and NGR3, respectively. In this study, we produced RNases NW and NGR3 in Escherichia coli and purified them to homogeneity. RNase NGR3 had non-absolute specificity toward polynucleotides, although RNase NW preferentially cleaved polyinosinic acid (Poly I). Both RNases NW and NGR3 were more active toward diribonucleoside monophosphates ApG, CpU, and GpU. Furthermore, kinetic parameters for RNase NW (Km, 0.778 mM and kcat, 1938 min(-1)) and RNase NGR3 (Km, 0.548 mM and kcat, 408 min(-1)) were calculated using GpU as a substrate.
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PMID:Expression of Nicotiana glutinosa ribonucleases in Escherichia coli. 1203 75

We previously cloned two distinct cDNA clones, NGR1 and NGR3, encoding S-like ribonucleases (RNases) induced by wounding and tobacco mosaic virus (TMV) infection, respectively, in Nicotiana glutinosa leaves. To gain insight into the regulatory mechanism of the RNase genes, we analyzed nucleotide sequences of the genes ngr1 (4.1 kbp) and ngr3 (5.3 kbp), containing their structural genes as well as 5'-flanking regions. The ngr1 gene is organized in three exons with two intervening introns, and ngr3 has four exons interrupted by three introns. Primer extension analyses localized single transcription initiation sites at -32 and -99 upstream of the translation initiation codons ATG in the genes ngr1 and ngr3, respectively. The beta-glucuronidase (GUS) reporter gene analysis with serial 5'-deletion mutants as well as a gel shift assay defined the wound-responsive region at residues -509 to -288 in gene ngr1 and a TMV-responsive region at the residues -401 to -174 in ngr3, respectively. Sequence search using PLACE and PlantCARE data bases showed that a wound-responsive element: the WUN-motif, occurs within the wound-responsive region in ngr1, while ngr3 contains several potential cis-regulating elements, such as the elicitor responsiveness element: the W-box, a TMV responsive element: GT1, and the WUN-motif at positions between -401 and -174. These findings suggested that some of these cis-elements may be involved in inducible expressions of ngr1 and ngr3. Furthermore, the gel shift assay suggested that the dissociation of protein factor(s) upon TMV-infection from the regulatory region may cause an inducible expression of ngr3.
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PMID:Genomic cloning of ribonucleases in Nicotiana glutinosa leaves, as induced in response to wounding or to TMV-infection, and characterization of their promoters. 1473 Jan 35