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1.
S. S. Sangaev E. A. Trifonova S. E. Titov A. V. Romanova Ya. S. Kolodyazhnaya M. V. Sapotsky V. I. Malinovsky A. V. Kochetov 《Russian Journal of Genetics》2010,46(1):117-119
Primary transformants of SR1 Nicotiana tabacum plants with RNA interference-based silencing of the gene for extracellular ribonuclease Nk1 were obtained. It was demonstrated that the profiles of ribonuclease activities of leaf protein extracts from these plants
lacked ribonuclease with electrophoretic mobility corresponding to that of the Nk1 protein. Primary transformants did not
differ phenotypically from control plants. They represent a new model for investigation of the biological role of extracellular
ribonucleases, including the molecular mechanisms of resistance to pathogens. 相似文献
2.
Petunia inflata, a species with gametophytic self-incompatibility, has previously been found to contain a large number of ribonucleases in the pistil. The best characterized of the pistil ribonucleases are the products of the S alleles, the S proteins, which are thought to be involved in self-incompatibility interactions. Here we report the characterization of a gene encoding another pistil ribonuclease of P. inflata, RNase X2. Degenerate oligonucleotides, synthesized based on the amino-terminal sequence of RNase X2, were used as probes to isolate cDNA clones, one of which was in turn used as a probe to isolate genomic clones containing the gene for RNase X2, rnx2. The deduced amino acid sequence of RNase X2 shows 42% to 71% identity to the 20 solanaceous S proteins reported so far, with the highest degree of similarity being to S3 and S6 proteins of Nicotiana alata. The cDNA sequence predicts a leader peptide of 22 amino acids, suggesting that RNase X2, like S proteins, is an extracellular ribonuclease. Also, similar to the S gene, rnx2 is expressed only in the pistil, and contains a single intron comparable in size and identical in location to that of the S gene. However, rnx2 is not linked to the S locus, and, in contrast to the highly polymorphic S gene, it is monomorphic. The possible biological function of RNase X2 is discussed. 相似文献
3.
Guanyl-specific ribonucleases from Bacillus intermedius and Bacillus pumilus are actively secreted under phosphate starvation by recombinant strains of Bacillus subtilis with native regulatory systems and by strains defective in some proteins of the Spo0A phosphorylation pathway. The level
of expression of ribonuclease genes has been shown to increase approximately sixfold in recombinant strains with mutation
in the spo0A gene and threefold in the spo0A/abrB mutants, as compared with native strains. These results demonstrate that the Spo0A protein regulates the production of ribonucleases
and thus acts as a repressor, while the AbrB protein is an activator of expression of the genes encoding ribonucleases from
Bacillus intermedius and Bacillus pumilus in Bacillus subtilis cells.
Original Russian Text ? V.V. Ul’yanova, V.I. Vershinina, M.A. Kharitonova, M.R. Sharipova, 2007, published in Mikrobiologiya,
2007, Vol. 76, No. 5, pp. 639–644. 相似文献
4.
Pancreatic ribonucleases from several species (whitetail deer, roe deer, guinea pig, and arabian camel) exhibit more than one amino acid at particular positions in their amino acid sequences. Since these enzymes were isolated from pooled pancreas, the origin of this heterogeneity is not clear. The pancreatic ribonucleases from 11 individual arabian camels (Camelus dromedarius) have been investigated with respect to the lysine-glutamine heterogeneity at position 103 (Welling et al., 1975). Six ribonucleases showed only one basic band and five showed two bands after polyacrylamide gel electrophoresis, suggesting a gene frequency of about 0.75 for the Lys gene and about 0.25 for the Gln gene. The amino acid sequence of bactrian camel (Camelus bactrianus) ribonuclease isolated from individual pancreatic tissue was determined and compared with that of arabian camel ribonuclease. The only difference was observed at position 103. In the ribonucleases from two unrelated bactrian camels, only glutamine was observed at that position.Part of this work has been carried out under the auspices of the Netherlands Foundation for Chemical Research (S.O.N.) and with financial aid from the Netherlands Organisation for the Advancement of Pure Research (Z.W.O.). 相似文献
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Summary Pancreatic ribonuclease from pronghorn (Antilocapra americana) was isolated and its amino acid sequence was determined from a tryptic digest of the performic acid-oxidized protein. Peptides were positioned by homology with other ribonucleases. Only peptides that differed in amino acid composition from the corresponding peptides of ox or goat ribonucleases were sequenced.In a most parsimonious tree of pancreatic ribonucleases, pronghorn and giraffe were placed together and these two were placed with the bovids, leaving the deer as a taxon separate from the other ruminants. The amino acid replacements that determine this tree topology are three rarely occurring replacements shared by pronghorn and giraffe. Notwithstanding their close phylogenetic relationship, both ribonucleases differ strongly in extent of glycosidation, net charge and antigenic properties. 相似文献
7.
Summary We present a sequence comparison of 12 S-allele-associated proteins from three solanaceous species with gametophytic self-incompatibility: Nicotiana alata, Petunia inflata, and Solanum chacoense. The allelic variants of the S-protein exhibit a very high degree of sequence diversity consistent with their function as recognition molecules. We identify 41 perfectly conserved residues, 18 of which are also conserved in two fungal ribonucleases, RNase T2 and RNase Rh. The residues conserved in both the S-proteins and the ribonucleases include two histidines essential for catalysis, four cysteines involved in disulfide bridges, and hydrophobic residues probably involved in the core structure of the proteins. This conservation between the two ribonucleases and the 12 divergent S-proteins confirms the previously recognized similarity between 3 more closely related N. alata S-proteins and these ribonucleases, and argues strongly for the functional importance of the ribonuclease activity of the S-protein in self-incompatibility. We also identify the 19 most variable residues, which are the prime candidates for the S-allele-specificity determinant. Twelve of these nineteen residues are clustered in two regions of hypervariability, designated HVa and HVb, which are also the most prominent hydrophilic regions of the S-protein. We suggest that these two regions might form parts of the putative pollen recognition site. Identification of these structural features forms a foundation for the study of the molecular basis of self-recognition and the biochemical mechanism of inhibition of self-pollen tube growth.On sabbatical leave from Biotechnology Center, General Foods USA, Tarrytown, NY 10591, USA 相似文献
8.
Ribosomal RNA is normally a stable molecule in bacterial cells with negligible turnover. Antibiotics which impair ribosomal
subunit assembly promote the accumulation of subunit intermediates in cells which are then degraded by ribonucleases. It is
predicted that cells expressing one or more mutated ribonucleases will degrade the antibiotic-bound particle less efficiently,
resulting in increased sensitivity to the antibiotic. To test this, eight ribonuclease-deficient strains of Escherichia coli were grown in the presence or absence of azithromycin. Cell viability and protein synthesis rates were decreased in these
strains compared with wild type cells. Degradation of 23S rRNA and recovery from azithromycin inhibition were examined by
3H-uridine labeling and by hybridization with a 23S rRNA specific probe. Mutants defective in ribonuclease II and polynucleotide
phosphorylase demonstrated hypersensitivity to the antibiotic and showed a greater extent of 23S rRNA accumulation and a slower
recovery rate. The results suggest that these two ribonucleases are important in 23S rRNA turnover in antibiotic-inhibited
E. coli cells. 相似文献
9.
Tobacco (Nicotiana tabacum L., cv. Samsun) leaf discs inoculated with tobacco mosaic virus (TMV) were treated with auxin-like herbicides 2,4-dichlorophenoxyacetic acid (2,4-D), 2-methyl-4-chlorophenoxyacetic acid (MCPA), 3-amino-1,2,4-triazol (Amitrol) and 6-chloro-2-ethylamino-4-isopropylamino-1,3,5-triazine (Atrazin). All herbicides in the concentration of 10–7 M enhanced the virus content (MCPA to 227.4 %, Amitrol to 218.1 % and Atrazin to 257.3 % of values found in TMV-infected, herbicide untreated discs). The 2,4-D alone did not affect the activity of the glucose-6-phosphate dehydrogenase and ribonucleases, but the 2,4-D treatment together with TMV infection raised their activities twice as high as in the untreated control discs. Polyacrylamide gel electrophoresis of acidic extracellular proteins washed from leaf discs treated with 2,4-D did not prove the induction of PR-proteins. 相似文献
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Singhania NA Dyer KD Zhang J Deming MS Bonville CA Domachowske JB Rosenberg HF 《Journal of molecular evolution》1999,49(6):721-728
The two eosinophil ribonucleases, eosinophil-derived neurotoxin (EDN/RNase 2) and eosinophil cationic protein (ECP/RNase
3), are among the most rapidly evolving coding sequences known among primates. The eight mouse genes identified as orthologs
of EDN and ECP form a highly divergent, species-limited cluster. We present here the rat ribonuclease cluster, a group of
eight distinct ribonuclease A superfamily genes that are more closely related to one another than they are to their murine
counterparts. The existence of independent gene clusters suggests that numerous duplications and diversification events have
occurred at these loci recently, sometime after the divergence of these two rodent species (∼10–15 million years ago). Nonsynonymous
substitutions per site (d
N) calculated for the 64 mouse/rat gene pairs indicate that these ribonucleases are incorporating nonsilent mutations at accelerated
rates, and comparisons of nonsynonymous to synonymous substitution (d
N / d
S) suggest that diversity in the mouse ribonuclease cluster is promoted by positive (Darwinian) selection. Although the pressures
promoting similar but clearly independent styles of rapid diversification among these primate and rodent genes remain uncertain,
our recent findings regarding the function of human EDN suggest a role for these ribonucleases in antiviral host defense.
Received: 8 April 1999 / Accepted: 22 June 1999 相似文献
13.
Stephania A. Cormier Kirsten A. Larson Shubing Yuan Trella L. Mitchell Kari Lindenberger Patricia Carrigan Nancy A. Lee James J. Lee 《Mammalian genome》2001,12(5):352-361
A unique family of ribonucleases was identified by exhaustive screening of genomic and cDNA libraries using a probe derived
from a gene encoding a ribonuclease stored in the mouse eosinophil secondary granule. This family contains at least 13 genes,
which encode ribonucleases, and two potential pseudogenes. The conserved sequence identity among these genes (∼70%), as well
as the isolation/purification of these ribonucleases from eosinophil secondary granules, has led us to conclude that these
genes form a unique clade in the mouse that we have identified as the Ear (Eosinophil-associated ribonuclease) gene family. Analyses of the nucleotide substitutions that have occurred among these ribonuclease genes reveal
that duplication events within this family have been episodic, occurring within three unique periods during the past 18 ×
106 years. Moreover, comparisons of non-synonymous (Ka) vs. synonymous (Ks) rates of nucleotide substitution show that although these genes conserve residues necessary for RNase activity, selective
evolutionary pressure(s) exist such that acquired amino acid changes appear to be advantageous. The selective advantage of
these amino acid changes is currently unclear, but the occurrence of this phenomenon in both the mouse and the human highlights
the importance of these changes for Ear and, therefore, eosinophil effector function(s).
Received: 25 October 2000 / Accepted: 18 December 2000 相似文献
14.
50 strains of Aspergillus fumigatus were studied for enzymatic and physiologic profile. Proteolytic and lipolytic activity were lacking. Various ribonucleases and sacchrolytic enzymes were found. 相似文献
15.
Eosinophil cationic protein/RNase 3 is another RNase A-family ribonuclease with direct antiviral activity. 总被引:5,自引:0,他引:5
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J B Domachowske K D Dyer A G Adams T L Leto H F Rosenberg 《Nucleic acids research》1998,26(14):3358-3363
Eosinophil cationic protein (ECP) is one of two RNase A-superfamily ribonucleases found in secretory granules of human eosinophilic leukocytes. Although the physiologic function of eosinophils [and thus of the two eosinophil ribonucleases, ECP and eosinophil-derived neurotoxin (EDN)] remains controversial, we have recently shown that isolated human eosinophils promote ribonuclease-dependent toxicity toward extracellular virions of the single-stranded RNA virus, respiratory syncytial virus, group B (RSV-B). We have also shown that recombinant human EDN (rhEDN) can act alone as a ribonuclease-dependent antiviral agent. In this work, we provide a biochemical characterization of recombinant human ECP (rhECP) prepared in baculovirus, and demonstrate that rhECP also promotes ribonuclease-dependent antiviral activity. The rhECP described here is N-glycosylated, as is native ECP, and has approximately 100-fold more ribonuclease activity than non-glycosylated rhECP prepared in bacteria. The enzymatic activity of rhECP was sensitive to inhibition by placental ribonuclease inhibitor (RI). Although rhECP was not as effective as rhEDN at reducing viral infectivity (500 nM rhECP reduced infectivity of RSV-B approximately 6 fold; 500 nM rhEDN, >50 fold), the antiviral activity appears to be unique to the eosinophil ribonucleases; no reduction in infectivity was promoted by bovine RNase A, by the amphibian ribonuclease, onconase, nor by the closely-related human ribonuclease, RNase k6. Interestingly, combinations of rhEDN and rhECP did not result in either a synergistic or even an additive antiviral effect. Taken together, these results suggest that that the interaction between the eosinophil ribonucleases and the extracellular virions of RSV-B may be specific and saturable. 相似文献
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Zhenodarova SM 《Prikladnaia biokhimiia i mikrobiologiia》2001,37(1):19-28
Results of studies of certain fungal extracellular ribonucleases mainly isolated from representatives of the genera Aspergillus and Penicillium are summarized. The isolation of these enzymes in highly purified states in the 1970-1980s strongly stimulated further studies of their structure, functions, and mechanisms of action. This also promoted the use of ribonucleases as catalysts in oligoribonucleotide syntheses and as objects of comparative and evolutionary biochemistry and other research works. Results of studies of the primary, secondary, and spatial structures of guanyl-specific fungal ribonucleases are reviewed. These studies revealed a high homology within the subfamilies of fungal, bacterial, and actinomycete RNases. Characteristics of the nonspecific Pb2 RNase are considered. 相似文献
19.
Low ribonuclease activity in cellular lysates of osmotic sensitive Saccharomyces cerevisiae mutants.
Pencho V. Venkov 《Molecular & general genetics : MGG》1979,175(1):111-112
Summary Cellular lysates with very low total ribonuclease activities are obtained by lysis of Saccharomyces cerevisiae VY1160 osmotic sensitive mutant cells in 1% sorbitol solution. These lysates could be used for isolation of intact polysomes and messenger RNA molecules, or for studying of specific ribonucleases. 相似文献
20.
A A Dement'ev N F Riabchenko I I Protasevich P N Golyshin A I Stepanov V M Orlov V N Pustovaev A A Makarov G P Moiseev M Ia Karpe?ski? 《Molekuliarnaia biologiia》1992,26(6):1338-1349
Intraspecific selection of Bacillus thuringiensis strains producing extracellular alkaline ribonucleases was carried out. Subtoxicus subspecies with increased expression of the enzyme was detected. A method was developed to isolate preparative amounts of homogeneous extracellular RNase of B. thuringiensis var. subtoxicus. The physico-chemical and catalytic properties of the enzyme was studied and compared with extracellular RNases of others Bacillus species. The conclusion about the structural and evolutional conservation of Bacillus extracellular RNases was drawn. 相似文献