| DNA synthesis | <molecular biology> The linking together of nucleotides (as deoxyribonucleotide triphosphates) to form DNA. In vivo, most synthesis is DNA replication, but incorporation of precursors also occurs in repair. In the special case of retroviruses, DNA synthesis is directed by an RNA template (see reverse transcriptase). (18 Nov 1997) |
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| DNA synthesiser | <molecular biology> A machine which automatically makes short, artificial polynucleotides or oligonucleotides with any desired sequence of nucleotide bases. (09 Oct 1997) |
| DNA technology, recombinant | A series of procedures used to join together (recombine) DNA segments. A recombinant DNA molecule is constructed (recombined) from segments from 2 or more different DNA molecules. Under certain conditions, a recombinant DNA molecule can enter a cell and replicate there, autonomously (on its own) or after it has become integrated into a chromosome. (12 Dec 1998) |
| DNA topoisomerase | <enzyme, molecular biology> An enzyme capable of altering the degree of supercoiling of double stranded DNA molecules. Various topoisomerases can increase or relax supercoiling, convert single stranded rings to intertwined double stranded rings, tie and untie knots in single stranded and duplex rings, catenate and decatenate duplex rings. Topoisomerase II of E. Coli = gyrase. (18 Nov 1997) |
| DNA topoisomerase (ATP-hydrolysing) | <enzyme> An ATP-requiring enzyme which, in the presence of magnesium ions, introduces negative supertwists into closed and possibly linear duplex DNA. The enzyme is implicated in DNA replication and transcription. It causes the storage of mechanical strain energy in the superhelical turns of DNA at the expense of ATP hydrolysis. Chemical name: DNA topoisomerase (ATP-hydrolysing) Registry number: EC 5.99.1.3 (12 Dec 1998) |
| DNA transfection | <molecular biology> A technique originally developed to allow viral infection of animal cells by uptake of purified viral DNA rather than by intact virus particles. Term is now generally used to describe applications of same methodology to introduction of other kinds of genes or gene fragments into cells as DNA, such as activated oncogenes from tumours into tissue culture cells. (18 Nov 1997) |
| DNA tumour virus | <oncology, virology> Virus with DNA genome that can cause tumours in animals. Examples are Papovaviridae, Adenoviridae and Epstein Barr virus. (18 Nov 1997) |
| DNA tumour viruses | DNA viruses producing malignant tumours. Of the six major groupings of DNA viruses four contain members which are actually or potentially oncogenic: the adenoviridae, the herpesviridae, the papovaviridae, and the poxviridae. (12 Dec 1998) |
| DNA twisting | <molecular biology> The coiling of a double-stranded DNA molecule in the opposite direction than the direction that the helix turns. (09 Oct 1997) |
| DNA typing | <molecular biology> See restriction fragment length polymorphism. (18 Nov 1997) |
| DNA unwinding protein | <molecular biology> A protein that will attach to single-stranded DNA after it has been unwound for replication or recombination, and help it stay unwound. (09 Oct 1997) |
| DNA, viral | Deoxyribonucleic acid that makes up the genetic material of viruses. (12 Dec 1998) |
| DNA virus | <molecular biology, virology> A virus in which the nucleic acid is double or single stranded DNA (rather than RNA). Major groups of double stranded DNA viruses are papovaviruses, adenoviruses, herpes viruses, large bacteriophages and poxviruses: of single stranded, parvoviruses and coliphages _X174 and M13. (18 Nov 1997) |
| DNA viruses | Viruses whose nucleic acid is DNA. (12 Dec 1998) |
| DNA writhing | <molecular biology> Coiling of a double-stranded DNA molecule in such a way that it crosses its own (longitudinal) axis. (09 Oct 1997) |