Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The gene coding for plasminogen has been compared with several abnormal genes from Japanese patients by the polymerase chain reaction and DNA sequence analysis. Two types of abnormal genes coding for plasminogen were identified in these patients. In the type I mutation, a guanosine in GCT coding for Ala-601 near the active-site histidine was replaced by an adenosine resulting in ACT coding for threonine. This mutation was also shown by the loss of a cleavage site for Fnu4HI endonuclease, a restriction enzyme that recognizes GCTGC but not ACTGC. In the type II mutation, a guanosine in GTC coding for Val-355 was replaced by a thymidine resulting in TTC coding for phenylalanine. This change was readily shown by digestion with Ava II endonuclease, a restriction enzyme that recognizes GGTCC and not GTTCC. The type I mutation has been found to be identical to a plasminogen variant identified in Japanese patients by amino acid sequence analysis and also detected by isoelectric focusing, whereas the type II mutation is a unique amino acid substitution in the connecting region between the third and fourth kringles in plasminogen. DNA sequence analysis also revealed that the abnormal genes carry several silent nucleotide substitutions located primarily within introns and 5' and 3' flanking regions.
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PMID:Two types of abnormal genes for plasminogen in families with a predisposition for thrombosis. 198 55

Organic synthesis and recombinant DNA techniques have been used to situate a single 1,N6-ethenoadenine (epsilon Ade) DNA adduct at an amber codon in the genome of an M13mp19 phage derivative. The deoxyhexanucleotide d[GCT(epsilon A)GC] was chemically synthesized by the phosphotriester method. Mild nonaqueous conditions were employed for deprotection because of the unstable nature of the epsilon Ade adduct in aqueous basic milieu. Physical studies involving fluorescence, circular dichroism, and 1H NMR indicated epsilon Ade to be very efficiently stacked in the hexamer, especially with the 5'-thymine. Melting profile and circular dichroism studies provided evidence of the loss of base-pairing capabilities attendant with formation of the etheno ring. The modified hexanucleotide was incorporated into a six-base gap formed in the genome of an M13mp19 insertion mutant; the latter was constructed by blunt-end ligation of d(GCTAGC) in the center of the unique SmaI site of M13mp19. Phage of the insertion mutant, M13mp19-NheI, produced light blue plaques on SupE strains because of the introduced amber codon. Formation of a hybrid between the single-strand DNA (plus strand) of M13mp19-NheI with SmaI-linearized M13mp19 replicative form produced a heteroduplex with a six-base gap in the minus strand. The modified hexamer [5'-32P]d-[GCT(epsilon A)GC], after 5'-phosphorylation, was ligated into this gap by using bacteriophage T4 DNA ligase to generate a singly adducted genome with epsilon Ade at minus strand position 6274. Introduction of the radiolabel provided a useful marker for characterization of the singly adducted genome, and indeed the label appeared in the anticipated fragments when digested by several restriction endonucleases. Evidence that ligation occurred on both 5' and 3' sides of the oligonucleotide also was obtained. The adduct was introduced into a unique NheI site, and it was observed that this restriction endonuclease was able to cleave the adducted genome, albeit at a lower rate compared to unmodified DNA. The M13mp19-NheI genome containing epsilon Ade will be used as a probe for studying mutagenesis and repair of this DNA adduct in Escherichia coli.
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PMID:Deoxyhexanucleotide containing a vinyl chloride induced DNA lesion, 1,N6-ethenoadenine: synthesis, physical characterization, and incorporation into a duplex bacteriophage M13 genome as part of an amber codon. 331 93

The characterization of the new restriction enzyme Eco47III recognizing a hexanucleotide palindromic sequence 5'AGC decreases GCT and cleaving, as indicated by the arrow, is reported. It was isolated from Escherichia coli strain RFL47. Another two specific endonuclease Eco47I (isoschizomer of AvaII) and Eco47II (isoschizomer of AsuI) were also found in this strain. There are two Eco47III recognition sites on lambda DNA at 20997 and 37060 basepairs. The central Eco47III fragment can be replaced by a cloned fragment in lambda vector mutant in tR2 gene; i.e., lambda gt.
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PMID:Three sequence-specific endonucleases from Escherichia coli RFL47. 631 23

The human AP endonuclease (Ape1 or ref-1) DNA base excision repair (BER) enzyme is a multifunctional protein that has an impact on a wide variety of important cellular functions including oxidative signaling, transcription factor regulation, and cell cycle control. It acts on mutagenic AP (baseless) sites in DNA as a critical member of the DNA BER repair pathway. Moreover, Ape1/ref-1 stimulates the DNA-binding activity of transcription factors (Fos-Jun, nuclear factor-kappaB, Myb, ATF/cyclic AMP-responsive element binding protein family, HIF-1alpha, HLF, PAX, and p53) through a redox mechanism and thus represents a novel component of signal transduction processes that regulate eukaryotic gene expression. Ape1/ref-1 has also been shown to be closely linked to apoptosis associated with thioredoxin, and altered levels of Ape1/ref-1 have been found in some cancers. In a pilot study, we have examined Ape1/ref-1 expression by immunohistochemistry in sections of germ cell tumors (GCTs) from 10 patients with testicular cancer of various histologies including seminomas, yolk sac tumors, and malignant teratomas. Ape1/ref-1 was expressed at relatively high levels in the tumor cells of nearly all sections. We hypothesized that elevated expression of Ape1/ref-1 is responsible in part for the resistance to therapeutic agents. To answer this hypothesis, we overexpressed the Ape1/ref-1 cDNA in the GCT cell line NT2/D1 using retroviral gene transduction with the vector LAPESN. Using an oligonucleotide cleavage assay and immunohistochemistry to assess Ape1/ref-1 repair activity and expression, respectively, we found that the repair activity and relative Ape1/ref-1 expression in GCT cell lines are directly related. NT2/D1 cells transduced with Ape1/ref-1 exhibited 2-fold higher AP endonuclease activity in the oligonucleotide cleavage assay, and this was reflected in a 2-3-fold increase in protection against bleomycin. Lesser protection was observed with gamma-irradiation. We conclude that: (a) Ape1/ref-1 is expressed at relatively high levels in some GCTs; (b) elevated expression of Ape1/ref-1 in testicular cancer cell lines results in resistance to certain therapeutic agents; and (c) Ape1/ref-1 expression in GCT cell lines determined by immunohistochemistry and repair activity assays parallels the level of protection from bleomycin. We further hypothesize that elevated Ape1/ref-1 levels observed in human testicular cancer may be related to their relative resistance to therapy and may serve as a diagnostic marker for refractory disease. To our knowledge, this is the first example of overexpressing Ape1/ref-1 in a mammalian system resulting in enhanced protection to DNA-damaging agents.
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PMID:Altered expression of Ape1/ref-1 in germ cell tumors and overexpression in NT2 cells confers resistance to bleomycin and radiation. 1128 Jul 90

The diastereomeric complexes Lambda- and Delta-[Ru(bpy)(2)(m-bpy-7p)]Cl(2), (bpy=2,2'-bipyridine, m-bpy-7p=4-methyl-4'-Arg-Gly-Asn-Ala-His-Glu-Arg-CONH(2)-2,2'-bipyridine) were synthesized and characterized and their binding properties to the deoxynucleotide duplexes d(5'-CGCGATCGCG-3')(2) and d(5'-GCGCTTAAGCGC-3')(2) were studied by means of (1)H NMR spectroscopy. 7p is part of the recognition loop of the restriction endonuclease MunI, a type II restriction enzyme from Mycoplasma unidentified which recognizes the palindromic hexanucleotide sequence C/AATTG and cleaves it as indicated by the slash. The Delta-isomer binds to the terminal CG/GC major groove of d(CGCGATCGCG)(2) decanucleotide, whereas the Lambda-isomer approaches the GCT/CGA sequence. On the other hand, weak binding of the Delta-isomer to the end of d(GCGCTTAAGCGC)(2) into two different orientations is observed. In the case of the Lambda-isomer, the bpy ligand(s) are located into the major groove of the central TT/AA sequence. The role of appended peptide sequences in sequence selectivity binding to DNA is being addressed.
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PMID:Synthesis and characterization of the diastereomers Lambda- and Delta-[Ru(bpy)2(m-bpy-L-Arg-Gly-L-Asn-L-Ala-L-His-L-Glu-L-Arg)]Cl2 1H NMR studies on their interactions with the deoxynucleotide duplex d[(5'-GCGCTTAAGCGC-3')2] and d[(5'-CGCGATCGCG-3')2]. 1562 Dec 96