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

We have isolated a 725-base-pair cDNA clone for human eosinophil-derived neurotoxin (EDN). EDN is a distinct cationic protein of the eosinophil's large specific granule known primarily for its ability to induce ataxia, paralysis, and central nervous system cellular degeneration in experimental animals (Gordon phenomenon). The open reading frame encodes a 134-amino acid mature polypeptide with a molecular mass of 15.5 kDa and a 27-residue amino-terminal hydrophobic leader sequence. The sequence of the mature polypeptide is identical to that reported for human urinary ribonuclease [Beintema, J. J., Hofsteenge, J., Iwama, M., Morita, T., Ohgi, K., Irie, M., Sugiyama, R. H., Schieven, G. L., Dekker, C. A. & Glitz, D. G. (1988) Biochemistry 27, 4530-4538] and to the amino-terminal sequence of human liver ribonuclease [Sorrentino, S., Tucker, G. K. & Glitz, D. G. (1988) J. Biol. Chem. 263, 16125-16131]; the cDNA encodes a tryptophan in position 7, which was previously unidentified in the amino acid sequences of EDN or the urinary and liver ribonucleases. Both EDN and the related granule protein, eosinophil cationic protein, have ribonucleolytic activity; sequence similarities among EDN, eosinophil cationic protein, ribonucleases from liver, urine, and pancreas, and angiogenin define a ribonuclease multigene family. mRNA encoding EDN was detected in uninduced HL-60 cells and was up-regulated in cells induced toward eosinophilic differentiation with B-cell growth factor 2/interleukin 5 and toward neutrophilic differentiation with dimethyl sulfoxide. EDN mRNA was detected in mature neutrophils even though EDN-like neurotoxic activity is not found in neutrophil extracts. These results suggest that neutrophils contain a protein that is closely related or identical to EDN.
 ...
PMID:Molecular cloning of the human eosinophil-derived neurotoxin: a member of the ribonuclease gene family. 273 98

Purkinje cell toxicity is one of the characteristic features of the Gordon phenomenon, a syndrome manifested by ataxia, muscular rigidity, paralysis, and tremor that may lead to death (Gordon, 1933). Two members of the RNase superfamily found in humans, EDN (eosinophil-derived neurotoxin) and ECP (eosinophil cationic protein), cause the Gordon phenomenon when injected intraventricularly into guinea pigs or rabbits. We have found that another member of the RNase superfamily, an antitumor protein called onconase, isolated from Rana pipiens oocytes and early embryos, will also cause the Gordon phenomenon when injected into the cerebrospinal fluid of guinea pigs at a dose similar to that of EDN (LD50, 3-4 micrograms). Neurologic abnormalities of onconase-treated animals were indistinguishable from those of EDN-treated animals, and histology showed dramatic Purkinje cell loss in the brains of onconase-treated animals. The neurotoxic activity of onconase correlates with ribonuclease activity. Onconase modified by iodoacetic acid to eliminate 70% and 98% of the ribonuclease activity of the native enzyme displays a similar decrease in ability to cause the Gordon phenomenon. In contrast, the homologous bovine pancreatic RNase A injected intraventricularly at a dose 5000 times greater than the LD50 dose of EDN or onconase is not toxic and does not cause the Gordon phenomenon. A comparison of the RNase activities of EDN, onconase, and bovine pancreatic RNase A using three pancreatic RNA substrates demonstrates that onconase is orders of magnitude less active enzymatically than EDN and RNase A. Thus, another member of the RNase superfamily in addition to EDN and ECP can cause the Gordon phenomenon.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Toxicity of an antitumor ribonuclease to Purkinje neurons. 830 53

Ataxia-telangiectasia (AT) is an autosomal recessive disorder characterized by progressive ataxia, telangiectasia, sinopulmonary infections, hypersensitivity to ionizing radiation, and combined immunodeficiency. Recently, the AT gene (ATM) was cloned and shown to be mutated in AT patients. In this report, mutation analysis of ATM was performed in a 24-year-old AT patient without immunodeficiency. ATM amplified with reverse transcriptase-polymerase chain reaction (RT-PCR) was screened with a ribonuclease (RNase) cleavage assay and auto-sequenced. This patient, a compound heterozygote, showed two mutations in ATM: one missense mutation leading to a Leu2656Pro substitution and the other to the truncation at codon 3047 (Arg-->ter). The latter mutation is within the phosphatidylinositol 3-kinase (PI 3-kinase)-like domain and the former is outside but close to the domain. The particular phenotype in our patient, no immunodeficiency, suggests incomplete functional loss of ATM protein. The clinical spectrum of AT caused by ATM mutations may be broader than previously thought. Further analysis of patients with similar phenotypes will make the relation between ATM genotype and phenotype clear.
 ...
PMID:Ataxia-telangiectasia without immunodeficiency: novel point mutations within and adjacent to the phosphatidylinositol 3-kinase-like domain. 945 Aug 74