Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

I have analyzed viral gene products expressed in five adenovirus type 2 (Ad2)- cytoplasmic, viral RNA which was selected by hybridization to cloned restriction endonuclease fragments of Ad2 DNA. Proteins synthesized in vitro were analyzed by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels and compared with those directed by RNAs prepared from productively infected cells. The early regions E1 and E4 of adenovirus type 2 (Ad2) were found to be expressed in all of five Ad2-transformed hamster embryo cells lines. RNA transcribed from early region E2, which codes for the 72,000-molecular-weight (72K) DNA-binding protein was detected in cell line HE1 only, and early region E3 was expressed exclusively in cell line HE4. RNA transcribed from the region between approximately 12 and 35 map units, coding for immediate early (13.5K, 52/53K) and immediate early proteins (13.6K, 16K, 17K, 87K), as well as RNA from late genes, was not found in any of the cell lines HE1 to HE5 had electrophoretic mobilities similar to those programmed by RNA from productively infected cells.
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PMID:Viral gene products in adenovirus type-2 transformed hamster cells. 709 53

The Saccharomyces cerevisiae RAD1 and RAD10 genes are required for the incision step of excision repair, and in addition, they function in mitotic recombination. The RAD1 and RAD10 proteins are associated in a tight complex, and genetic studies have indicated that complex formation is essential for the RAD1/RAD10 controlled biological activities. We had previously purified the RAD10 protein to near homogeneity from yeast and shown that it is a DNA-binding protein with a strong preference for single-stranded DNA. In this study, we purify the RAD1 protein to near homogeneity from yeast and show that it also binds single-stranded DNA preferentially and that the RAD1/RAD10 complex possesses an endonuclease activity. We characterize the RAD1/RAD10 endonuclease activity on both single-stranded and double-stranded DNAs, using agarose gel electrophoresis and trichloroacetic acid precipitation. The RAD1/RAD10 nuclease exhibits a much higher level of activity on single-stranded DNA than double-stranded DNA. The susceptibility of double-stranded DNA to nicking by the RAD1/RAD10 enzyme is markedly dependent on the degree of negative superhelicity, such that a 15-fold increase in nicking rate is observed from superhelical state sigma = zero to sigma = -0.08. The enzyme produces 3'-hydroxyl and 5'-phosphate termini on both single- and double-stranded DNAs. We discuss the role of RAD1/RAD10 endonuclease in nucleotide excision repair and in mitotic recombination.
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PMID:Purification and characterization of the Saccharomyces cerevisiae RAD1/RAD10 endonuclease. 825 64

Cell type in the yeast Saccharomyces cerevisiae is determined by information present at the MAT locus. Cells can switch mating types when cell-type information located at a silent locus, HML or HMR, is transposed to the MAT locus. The HML and HMR loci are kept silent through the action of a number of proteins, one of which is the DNA-binding protein, ABF1. We have identified a binding site for ABF1 within the Ya region of MATa and HMRa. In order to examine the function of this ABF1-binding site, we have constructed strains that lack the site in the MATa or HMRa loci. Consistent with the idea that ABF1 plays a redundant role in silencing, it was found that a triple deletion of the ABF1-binding sites at HMRE, Ya and I did not permit the expression of HMRa. We have also shown that chromosomal deletion of the binding site at MATYa had no effect on the level of cutting by the HO endonuclease nor on the amount of mating-type switching observed. Similarly, chromosomal deletion of all three ABF1-binding sites at HMRa had no effect on the directionality of mating-type switching.
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PMID:Functional analysis of the ABF1-binding sites within the Ya regions of the MATa and HMRa loci of Saccharomyces cerevisiae. 853 7

The histone-like protein HU isolated from Escherichia coli exhibited, after several purification steps, a Mg(2+)-dependent nuclease activity. We show here that this activity can be dissociated from HU by a denaturation-renaturation step, and is due to a small fraction of ribosomal protein S16 co-purifying with HU. S16 is an essential component of the 30S ribosomal particles. We have cloned, overproduced, and purified a histidine-tagged S16 and shown that this protein is a DNA-binding protein carrying a Mg(2+)-Mn(2+)-dependent endonuclease activity. This is an unexpected property for a ribosomal protein.
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PMID:The Escherichia coli ribosomal protein S16 is an endonuclease. 873 Aug 73

Human lymphocytes were X-irradiated at doses 0-10(-2) Gy and allowed to repair for some time. Nuclei were prepared and digested with restriction endonuclease Rsa I to selectively release 28S RNA gene fragment fraction, containing the DNA-binding protein, Hpa II digestion of nuclei was used to investigate the methylation of the 28S RNA gene fragment. There was a differential enrichment of 28S RNA gene binding protein for different X-ray doses with maximum enrichment for dose 2-3 x 10(-2) Gy with following diminish to 10 x 10(-2). The enrichment of less methylated fractions of 28S RNA gene was observed during X-irradiation. This might be explained by a different X-ray-induced changes of methylated and unmethylated rDNA binding with nuclear proteins. The possible mechanism for this phenomena are discussed.
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PMID:[Changes induced by low doses of ionizing radiation in the accessibility to DNA restriction enzymes of the ribosomal gene system of human lymphocytes]. 902 93

The product of the ATM gene, which is mutated in ataxia telangiectasia, is a nuclear phosphoprotein, and it involves the activation of the p53 pathway after ionizing radiation. Here we show that the ATM protein is constitutively associated with double strand DNA and that the interaction increases when the DNA is exposed to ionizing radiation. The ATM protein also had affinity to restriction endonuclease PvuII-digested DNA, but not to UV-irradiated DNA nor X-irradiated single-stranded DNA. The immunoprecipitation experiment detected very weak association between ATM and DNA-PK proteins, and immunodepletion of DNA-PK showed little or no effect on the interaction of the ATM protein with damaged DNA, indicating that an interaction with DNA-PK might not be required for the recruitment of the ATM protein to damaged DNA. Furthermore, the association was also confirmed in xrs-5 and xrs-6e cells, which are Chinese hamster ovary mutant cell lines defective in Ku80 function. These results indicate that the ATM protein is recruited to the site of DNA damage and it recognizes double strand breaks by itself or through an association with other DNA-binding protein other than DNA-PK and Ku80 proteins.
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PMID:Recruitment of ATM protein to double strand DNA irradiated with ionizing radiation. 1046 90

The PvuII restriction-modification system is a type II system, which means that its restriction endonuclease and modification methyltransferase are independently active proteins. The PvuII system is carried on a plasmid, and its movement into a new host cell is expected to be followed initially by expression of the methyltransferase gene alone so that the new host's DNA is protected before endonuclease activity appears. Previous studies have identified a regulatory gene (pvuIIC) between the divergently oriented genes for the restriction endonuclease (pvuIIR) and modification methyltransferase (pvuIIM), with pvuIIC in the same orientation as and partially overlapping pvuIIR. The product of pvuIIC, C. PvuII, was found to act in trans and to be required for expression of pvuIIR. In this study we demonstrate that premature expression of pvuIIC prevents establishment of the PvuII genes, consistent with the model that requiring C. PvuII for pvuIIR expression provides a timing delay essential for protection of the new host's DNA. We find that the opposing pvuIIC and pvuIIM transcripts overlap by over 60 nucleotides at their 5' ends, raising the possibility that their hybridization might play a regulatory role. We furthermore characterize the action of C. PvuII, demonstrating that it is a sequence-specific DNA-binding protein that binds to the pvuIIC promoter and stimulates transcription of both pvuIIC and pvuIIR into a polycistronic mRNA. The apparent location of C. PvuII binding, overlapping the -10 promoter hexamer and the pvuIICR transcriptional starting points, is highly unusual for transcriptional activators.
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PMID:Role and mechanism of action of C. PvuII, a regulatory protein conserved among restriction-modification systems. 1062 96

Ho endonuclease of Saccharomyces cerevisiae is a homing endonuclease that makes a site-specific double-strand break in the MAT gene in late G(1). Here we show that Ho is rapidly degraded via the ubiquitin-26S proteasome system through two ubiquitin-conjugating enzymes UBC2(Rad6) and UBC3(Cdc34). UBC2(Rad6) is complexed with the ring finger DNA-binding protein Rad18, and we find that Ho is stabilized in rad18 mutants. We show that the Ho degradation pathway involving UBC3(Cdc34) goes through the Skp1/Cdc53/F-box (SCF) ubiquitin ligase complex and identify a F-box protein, Yml088w, that is required for Ho degradation. Components of a defined pathway of the DNA damage response, MEC1, RAD9, and CHK1, are also necessary for Ho degradation, whereas functions of the RAD24 epistasis group and the downstream effector RAD53 have no role in degradation of Ho. Our results indicate a link between the endonuclease function of Ho and its destruction.
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PMID:Functions of the DNA damage response pathway target Ho endonuclease of yeast for degradation via the ubiquitin-26S proteasome system. 1096 70

Kinetoplast DNA (kDNA), the mitochondrial DNA of the trypanosomatid Crithidia fasciculata, is a unique structure containing 5,000 DNA minicircles topologically linked into a massive network. In vivo, the network is condensed into a disk-shaped structure. Replication of minicircles initiates at unique origins that are bound by universal minicircle sequence (UMS)-binding protein (UMSBP), a sequence-specific DNA-binding protein. This protein, encoded by a nuclear gene, localizes within the cell's single mitochondrion. Using immunofluorescence, we found that UMSBP localizes exclusively to two neighboring sites adjacent to the face of the kDNA disk nearest the cell's flagellum. This site is distinct from the two antipodal positions at the perimeter of the disk that is occupied by DNA polymerase beta, topoisomerase II, and a structure-specific endonuclease. Although we found constant steady-state levels of UMSBP mRNA and protein and a constant rate of UMSBP synthesis throughout the cell cycle, immunofluorescence indicated that UMSBP localization within the kinetoplast is not static. The intramitochondrial localization of UMSBP and other kDNA replication enzymes significantly clarifies our understanding of the process of kDNA replication.
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PMID:Intramitochondrial localization of universal minicircle sequence-binding protein, a trypanosomatid protein that binds kinetoplast minicircle replication origins. 1135 34

The pseudorabies virus (PRV) DNase is an alkaline exonuclease and endonuclease, which exhibits an Escherichia coli RecBCD-like catalytic function. The PRV DNA-binding protein (DBP) promotes the renaturation of complementary single strands of DNA, which is an essential function for recombinase. To investigate the functional and physical interactions between PRV DBP and DNase, these proteins were purified to homogeneity. PRV DBP stimulated the DNase activity, especially the exonuclease activity, in a dose-dependent fashion. Acetylation of DBP by acetic anhydride resulted in a loss of DNA-binding ability and a 60% inhibition of the DNase activity, suggesting that DNA-binding ability of PRV DBP was required for stimulating the DNase activity. PRV DNase behaved in a processive mode; however, it was converted into a distributive mode in the presence of DBP, implying that PRV DBP stimulated the dissociation of DNase from DNA substrates. The physical interaction between DBP and DNase was further analyzed by enzyme-linked immunosorbent assay, and a significant interaction was observed. Thus, these results suggested that PRV DBP interacted with PRV DNase and regulated the DNase activity in vitro.
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PMID:Pseudorabies virus DNA-binding protein stimulates the exonuclease activity and regulates the processivity of pseudorabies virus DNase. 1205 18


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