Deoxyribonuclease Iv: A New Exonuclease From Mammalian Tissues

Lindahl, Tomas; Gally, Joseph A.; Edelman, Gerald M.

doi:10.1073/pnas.62.2.597

Cited by 103 publications

(65 citation statements)

References 24 publications

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“…These activities are distinct from the DNA endonucleases DNase I and DNase II. DNase IV was subsequently renamed Flap Endonuclease 1 (FEN1), and was shown to function in the processing of 5' single stranded overhangs that arise during lagging-strand DNA replication, DNA repair and recombination [8,9]. DNase III (TREX1) was found to encode a nonprocessive 3'-5' DNA exonuclease with a preference for ssDNA or mispaired 3' termini [10,11].…”

Section: A Brief Summary Of Mammalian Dna Exonucleasesmentioning

confidence: 99%

TREX1 DNA exonuclease deficiency, accumulation of single stranded DNA and complex human genetic disorders

O’Driscoll

2008

DNA Repair

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Section: A Brief Summary Of Mammalian Dna Exonucleasesmentioning

confidence: 99%

TREX1 DNA exonuclease deficiency, accumulation of single stranded DNA and complex human genetic disorders

O’Driscoll

2008

DNA Repair

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“…The standard assays for DNase I11 and DNase IV measure the conversion of a radioactive polymer to acid-soluble products [15,17]. The DNase IV assay is only linear over a limited concentration range [17] ; the action of this enzyme was therefore studied at relatively low concentrations of enzyme activity.…”

Section: Assaysmentioning

confidence: 99%

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confidence: 99%

“…One of these enzymes, DNase 111, attacks both single-stranded and double-stranded DNA from the 3'-end [15]. The other enzyme, DNase IV, degrades double-stranded DNA and attacks at the 5'-termini [16,17]. Either of these exonucleases would seem to be suited to remove damaged residues from DNA, as they both release a small amount of dinucleotides in addition to mononucleotides during their action on unirradiated DNA in vitro.…”

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Excision of Pyrimidine Dimers from Ultraviolet‐Irradiated DNA by Exonucleases from Mammalian Cells

Lindahl

1971

European Journal of Biochemistry

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Two DNA specific exonucleases, DNase I11 and DNase IV, are present in mammalian cell nuclei. The activity of the purified enzymes with ultraviolet-irradiated polydeoxynucleotides and DNA as substrates has been investigated. DNase I11 shows a very poor ability to release pyrimidine dimers, although excision can be demonstrated by using high concentrations of enzyme. In contrast, DNase IV liberates h e r s in an effective fashion in vitro, and is a likely candidate to serve in this function also in vivo. The pyrimidine dimers are released by DNase IV as parts of oligonucleotides containing 5-8 residues. Neither of the two exonucleases is markedly inhibited by caffeine.When living cells are exposed to ultraviolet light, the main lesions produced are pyrimidine dimers in DNA, in particular dimers between adjacent thymine residues [l]. Such dimers are formed with similar efficiency in bacterial and mammalian cells [2], and both types of cells possess repair mechanisms that reduce the damaging effect of these structural defects in the DNA. One mechanism of repair depends on the excision of the pyrimidine dimers, followed by repair replication a t the single-stranded gaps thus produced in the DNA, and subsequent rejoining of the strand interruptions [3-71. While this type of DNA repair was originally discovered and characterized in microbial systems, the processes of pyrimidine dimer excision, repair replication, and joining of broken strands have now also been demonstrated to occur in mammalian cells as a consequence of radiation damage [8-lo]. Moreover, this mode of DNA repair is apparently of physiological sigdcance in man, as a loss of the ability to remove pyrimidine dimers from DNA seems to be the cause of the hereditary disease Xeroderma pigmentosum in which the patients are abnormally sensitive to ultraviolet light [ 111.It has been shown in bacteria that the excision of pyrimidine dimers from DNA requires two different enzymes : an endonuclease that specifically attacks ultraviolet-irradiated DNA and catalyzes the formaUnusual Abbreviations. Poly(dA), a homopolymer of deoxyadenylate ; poly(dT), a homopolymer of deoxythymidylate; poly(dA) * poly(dT), a double-stranded polymer composed of poly(dA) and poly(dT) ; poly[d(A-T)], an alternating double-stranded copolymer of deoxyadenylate and deoxythymidylate.All tritium-labeled polymers are labeled in the thymine residues.tion of a single-strand break close to the dimer, and an exonuclease that attacks at the strand interruption and has the property of being able to effectively release pyrimidine dimers from DNA [12,13]. The situation in mammalian cells again seems similar, as cells from a case of Xeroderma pigmentosum could excise damaged residues from irradiated DNA if adjacent single-strand breaks were introduced by non-enzymatic artificial means, i. e . the required endonuclease activity apparently was lacking but the exonuclease was present [la].Two different DNA-specific exonucleases, localized in the cell nuclei, have recently been found in mammalian tissues....

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“…More detailed studies have shown that 5Ј nucleases of this type specifically recognize bifurcated ends of double-stranded regions and remove single-stranded 5Ј arms by cutting the phosphodiester bond after the first base pair of the duplex, leaving a 3Ј hydroxyl end (2). A mammalian enzyme with functional similarity to the 5Ј-exonuclease domain of E. coli polymerase I was isolated nearly 30 years ago (4). Later, additional members of this group of enzymes called flap endonucleases (FEN1) from Eukarya and Archaea were shown to possess a nearly identical structure-specific activity (5-8), although they have limited sequence similarity to the bacterial 5Ј-exonuclease proteins.…”

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A Comparison of Eubacterial and Archaeal Structure-specific 5′-Exonucleases

Kaiser

Lyamicheva

et al. 1999

Journal of Biological Chemistry

142

149

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The 5-exonuclease domains of the DNA polymerase I proteins of Eubacteria and the FEN1 proteins of Eukarya and Archaea are members of a family of structurespecific 5-exonucleases with similar function but limited sequence similarity. Their physiological role is to remove the displaced 5 strands created by DNA polymerase during displacement synthesis, thereby creating a substrate for DNA ligase. In this paper, we define the substrate requirements for the 5-exonuclease enzymes from Thermus aquaticus, Thermus thermophilus, Archaeoglobus fulgidus, Pyrococcus furiosus, Methanococcus jannaschii, and Methanobacterium thermoautotrophicum. The optimal substrate of these enzymes resembles DNA undergoing strand displacement synthesis and consists of a bifurcated downstream duplex with a directly abutted upstream duplex that overlaps the downstream duplex by one base pair. That single base of overlap causes the enzymes to leave a nick after cleavage and to cleave several orders of magnitude faster than a substrate that lacks overlap. The downstream duplex needs to be 10 base pairs long or greater for most of the enzymes to cut efficiently. The upstream duplex needs to be only 2 or 3 base pairs long for most enzymes, and there appears to be interaction with the last base of the primer strand. Overall, the enzymes display very similar substrate specificities, despite their limited level of sequence similarity.The 5Ј nuclease domains of DNA polymerase I from Escherichia coli and Thermus aquaticus were the first extensively characterized members of a large class of structure-specific 5Ј-exonucleases (1, 2). Initially it was proposed that these enzymes work as true exonucleases removing predominantly mono-or dinucleotides from the 5Ј end of double-stranded DNA (3). More detailed studies have shown that 5Ј nucleases of this type specifically recognize bifurcated ends of double-stranded regions and remove single-stranded 5Ј arms by cutting the phosphodiester bond after the first base pair of the duplex, leaving a 3Ј hydroxyl end (2). A mammalian enzyme with functional similarity to the 5Ј-exonuclease domain of E. coli polymerase I was isolated nearly 30 years ago (4). Later, additional members of this group of enzymes called flap endonucleases (FEN1) from Eukarya and Archaea were shown to possess a nearly identical structure-specific activity (5-8), although they have limited sequence similarity to the bacterial 5Ј-exonuclease proteins.The substrate specificities of the FEN1 enzymes and the eubacterial and related bacteriophage enzymes have been examined and found to be similar for all enzymes (2, 5, 6, 8 -11). The minimal requirement for cleavage is a bifurcated duplex with a free 5Ј end. The presence of an upstream primer that directly abuts the downstream strand stimulates cleavage, but its precise effect on the site of cleavage remains unclear. In the majority of studies that were done with the flap substrate described in Harrington et al. (5), the enzymes leave predominately a 1-nucleotide gap or 1-nucleotide overlap between t...

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Deoxyribonuclease Iv: A New Exonuclease From Mammalian Tissues

Cited by 103 publications

References 24 publications

TREX1 DNA exonuclease deficiency, accumulation of single stranded DNA and complex human genetic disorders

TREX1 DNA exonuclease deficiency, accumulation of single stranded DNA and complex human genetic disorders

Excision of Pyrimidine Dimers from Ultraviolet‐Irradiated DNA by Exonucleases from Mammalian Cells

A Comparison of Eubacterial and Archaeal Structure-specific 5′-Exonucleases

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