DNA repair

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DNA repair

any of the processes in the CELL in which damaged DNA is recognized and repaired. The process may involve precise reversal of the damage, or removal of the damage followed by replacement with normal DNA. See, for example, DARK REPAIR, EXCISION REPAIR, MISMATCH REPAIR.

DNA


DNA binding proteins
are of two general types, histone proteins which are part of the unit structure of chromosomes called nucleosomes and nonhistone proteins which are present in small amounts and include regulatory proteins.
chromosomal DNA
circular DNA
a DNA molecule that is a closed-ring structure, found in mitochondria, prokaryote chromosomes, plasmids, and certain viruses.
closed DNA complexes
the first of two kinetically distinct steps required for RNA polymerase to initiate transcription in which the RNA polymerase holoenzyme binds electrostatically to the promoter DNA.
DNA construct
a DNA molecule which has been inserted into a cloning vector.
copy DNA
a DNA copy of mRNA which contains only regulatory and coding sequences, i.e. introns have been removed. mRNA is copied into double-stranded DNA using reverse transcriptase; the cDNA can then be cloned and amplified and introduced into an expression vector (plasmid or phage) and its protein product produced in either bacterial, yeast, insect or mammalian cells. Called also cDNA.
DNA deletion
DNA double helix
see double helix.
duplex DNA
double-stranded DNA.
end labeling DNA
methods for labeling DNA with radioisotopes or other detectable marker molecules at the ends using the terminal transferase 3′-labeling or polynucleotide kinase for 5′-labeling.
episomal DNA
that present in a cell as extra chromosomal; exemplified by plasmids of prokaryotic cells. See plasmid.
eukaryotic DNA
exogenous DNA
the DNA that has been introduced into a host by cloning.
DNA glycosylases
enzymes involved in the excision-repair mechanisms for DNA.
heteroduplex DNA
duplex DNA with each strand from a different origin.
DNA gyrase
see gyrase.
DNA library
a collection of cloned DNA molecules from a genome.
DNA ligase
an enzyme that seals nicks in the DNA helix, joins Okazaki fragments together during DNA replication and is essential in recombinant DNA technology for DNA cloning.
DNA microarray
an ordered set of thousands of different oligonucleotides immobilized on a microscope slide or other solid surface used for the detection of cognate nucleotide sequences such as the pattern of gene expression in a particular cell population by hybridization with fluorescently labeled cDNA prepared from total mRNA isolated from the cells.
mobile DNA
a sequence present in the variable locations on the chromosome. Called also jumping genes. See also retrotransposon and transposable genetic elements.
open DNA complex
a local opening of about 10 base pairs formed at the transcription initiation site following the electrostatic binding of RNA polymerase holoenzyme to the promoter region.
DNA polymerase
of Escherichia coli; has three distinct enzymatic activities: (a) a 5′ to 3′ polymerase activity which, under the direction of a template DNA, catalyzes the addition of mononucleotide units, produced from deoxynucleoside 5′-triphosphates, to the 3′-hydroxyl terminus of a primer chain; (b) a 5′ to 3′ exonuclease active only on duplex DNA; (c) a 3′ to 5′ exonuclease primarily active on single-stranded DNA which can selectively remove mismatched terminal nucleotides, thus carrying out a proofreading function. Additionally it catalyzes both the pyrophosphorolysis of DNA, a reaction which is the reverse of polymerization, and pyrophosphate exchange which represents a repetitive sequence of nucleotide addition and pyrophosphorolysis.
DNA probe
see probe (2).
DNA repair
a series of enzymatic mechanisms whereby errors or damage to one of the two DNA strands are removed by excision and replaced by correct nucleotides using the undamaged strand as template. The mechanisms include removal of lesions of depurination and DNA glycosylases which recognize altered bases.
repeat DNA, repetitive DNA
includes (a) satellite DNA and so-called (b) interspersed repeated DNA sequences. The latter are interspread throughout the chromosomes in hundreds of thousands of individual copies, each about 300 nucleotides long; they are, unlike satellite DNA, transcribed.
satellite DNA
serially repeated DNA sequences of one or a few nucleotides with a repeat length of up to 250 nucleotides that are not transcribed and commonly located in the heterochromatin associated with the centrometric regions of chromosomes.
selfish DNA
a mobile DNA element that appears to have no function except to replicate itself. Part of junk DNA.
DNA sequencing
determining the order of nucleotides in DNA from which amino acid in a polypeptide chain can be predicted.
single-copy DNA
the fraction of DNA that contains most of the protein-coding genes and reassociates most slowly.
single-stranded DNA
produced when double-stranded DNA is denatured or found naturally in some viruses.
spacer DNA
single-copy DNA sequences which do not encode proteins or functional RNA molecules.
supercoiled DNA
the double helix is itself twisted.
superhelical DNA
a twisted structure formed by circular DNA molecules. See also supercoiled DNA (above).
DNA transcription
DNA translation
unique DNA
DNA sequences that occur only once in the haploid genome.
DNA viruses
contain a single molecule of DNA that is either double or single stranded. Parvoviruses and circoviruses are single stranded, hepadnaviruses are partially double stranded and all others are double stranded. DNA virus families are: Poxviridae, Asfarviridae,Herpesviridae, Adenoviridae, Papovaviridae, Parvoviridae, Circoviridae, and Hepadnaviridae.
Z-DNA
an alternative structural form of DNA which differs from the more commonly occurring B- and related A-form in that the helix is left handed compared with the right hand helixes of B- and A-forms. Z is for zig-zag. The functional significance of Z-DNA is unknown.
References in periodicals archive ?
DNA damage results when UV light induces covalent bonds between nucleic acid base pairs and forms thymine dimers, which can alter tumor suppressor gene p53 function, thereby increasing the risk of cutaneous cancers and aging.
Ultraviolet (UV) radiation exposure can cause DNA damage and may be one of the contributing factors in the global amphibian extinction crisis.
While downsizing might enable these cells to replicate faster, it also seems to render them less able to withstand DNA damage.
Scientists have identified a plant extract that-taken orally prior to sun exposure--inhibits UV-triggered DNA damage.
The common consensus is that aging is the result of DNA damage accumulation, essentially the bodys failure to implement processes to completely repair its DNA over the years.
The formation of reactive hydroxyl radicals and reactive prostaglandin precursors during the spawning process may render these brood stock animals susceptible to DNA damage.
Gill cells of mussels were used to determine the DNA damage by comet assay.
Nor have they figured out how the accumulation of DNA damage leads to cancer.
Researchers are investigating whether veliparib, a PARP inhibitor, in combination with DNA damaging therapies, such as chemotherapy or radiation, may lessen the repair of DNA damage in cancer cells, eventually causing some cells to die.
Dr Boutlon joins the company to lead the development of its DNA Damage Response programme and in assisting the business development team in identifying new pipeline opportunities in the DNA Damage Response sector.
The present study was undertaken to examine the DNA damage induced by binary metal mixture (cadmium-lead) in peripheral blood erythrocytes of freshwater carp, Cyprinus carpio by using Comet bioassay.
If left unrepaired, DNA damage can cause mutations such as base substitutions and chromosomal translocations that disrupt normal gene expression or create abnormal proteins that are detrimental to cellular function or viability [6].