| DNA-directed RNA polymerase | <enzyme> A group of enzymes that catalyses DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesised. Chemical name: Nucleoside-triphosphate:RNA nucleotidyltransferase (DNA-directed) Registry number: EC 2.7.7.6 (12 Dec 1998) |
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| DNA-driven reaction | <molecular biology> A lab technique to mark highly-repeated DNA sequences with a radioactive RNA tracer, by having a much larger amount of complementary DNA molecules than radioactive RNA tracer molecules. (09 Oct 1997) |
| DNA duplex | <molecular biology> The double-stranded DNA molecule, which has a double helix (usually right-handed) structure. (09 Oct 1997) |
| DNA entry nuclease | <chemical> Mw 75kda; from membranes of competent bacillus subtilis cells; shows DNA-binding and nuclease activity; believed to be involved in entry of DNA into competent b subtilis cells (26 Jun 1999) |
| DNA excision | <molecular biology> The removal of a damaged segment of a DNA molecule by a group of DNA repair enzymes in order to repair the molecule. (09 Oct 1997) |
| DNA filter assay | <molecular biology> A lab technique used to identify the complementary base sequences of DNA. It involves immobilising the DNA on a filter and putting it in a solution that contains radioactively-labelled probe DNA or RNA molecules. (09 Oct 1997) |
| DNA fingerprint | <molecular biology> The unique pattern of DNA fragments identified by Southern hybridisation (using a probe that binds to a polymorphic region of DNA) or by polymerase chain reaction (using primers flanking the polymorphic region). (09 Oct 1997) |
| DNA fingerprinting | <molecular biology> See restriction fragment length polymorphism. (18 Nov 1997) |
| DNA footprinting | <molecular biology> Technique for identifying the recognition site of DNA binding proteins: See: footprinting. (18 Nov 1997) |
| DNA fragmentation | Endonucleolytic cleavage of genomic DNA into oligonucleosomal fragments at internucleosomal sites. DNA fragmentation along with chromatin condensation are considered the hallmarks of apoptosis. (12 Dec 1998) |
| DNA, fungal | Deoxyribonucleic acid that makes up the genetic material of fungi. (12 Dec 1998) |
| DNA gap | A localised loss of one of the two strands in the double helix of DNA. (05 Mar 2000) |
| DNA gene | <molecular biology> Any of a number of genes found in the bacteria Escherichia coli which makes proteins that are essential for DNA replication. (09 Oct 1997) |
| DNA glycosylase | <enzyme, molecular biology> Class of enzymes involved in DNA repair. They recognise altered bases in DNA and catalyse their removal by cleaving the glycosidic bond between the base and the deoxyribose sugar. at least 20 such enzymes occur in cells. (18 Nov 1997) |
| DNA gyrase | <enzyme, molecular biology> A type II topoisomerase of Escherichia coli, that is essential for DNA replication. This enzyme can induce or relax supercoiling. (18 Nov 1997) |