| intervening sequence | <molecular biology> Alternative but uncommon name for an intron. (18 Nov 1997) |
|---|---|
| tandem repeat sequence | <molecular biology> Multiple copies of the same base sequence on a chromosome, used as a marker in physical mapping. (09 Oct 1997) |
| termination sequence | <molecular biology> The three codons, UAA known as ochre, UAG as amber and UGA as opal, that do not code for an amino acid but act as signals for the termination of protein synthesis. They are not represented by any tRNA and termination is catalysed by protein release factors. There are two release factors in E. Coli, RF1 recognises UAA and UAG, RF2 recognises UAA and UGA. Eukaryotes have a single GTP requiring factor, eRF. See: ochre suppressor, amber suppressor. (13 Jan 1998) |
| enhancer sequence | <molecular biology> A nucleotide sequence, located as many as several thousand base pairs away in either direction from the target gene, which enhances transcription of that gene. (14 Nov 1997) |
| evolutionarily conserved sequence | A base sequence in a DNA molecule (or an amino acid sequence in a protein) that has remained essentially unchanged throughout evolution. (12 Dec 1998) |
| Expressed Sequence Tag | <molecular biology> Expressed sequence tags are sequence tagged sites derived from cDNAs. See: sequence tagged site. Acronym: EST (06 Aug 1998) |
| flanking sequence | <molecular biology> Short DNA sequences bordering a transcription unit. Often these do not code for proteins. (18 Nov 1997) |
| leader sequence | <molecular biology> In the regulation of gene expression for enzymes concerned with amino acid synthesis in prokaryotes, the leader sequence codes for the leader peptide that contains several residues of the amino acid being regulated. Transcription is closely linked to translation and if translation is retarded by limited supply of amino acyl tRNA for the specific amino acid, the mode of transcription of the leader sequence permits full transcription of the operon genes, otherwise complete transcription of the leader sequence prematurely terminates transcription of the operon. (18 Nov 1997) |
| A-DNA | A form of DNA in which the helix is right-handed and the overall appearance is short and broad. (05 Mar 2000) |
| a-form DNA | <molecular biology> One of several forms that can be assumed by a double helix. A-DNA is stable in dehydrated conditions. This form is less common than the dominant form found under physiological conditions -- beta-DNA. This form is also assumed by DNA-RNA hybrid helices and by regions of double-stranded RNA. It is a right-handed helix and is a more compact form than beta-DNA. (09 Oct 1997) |
| antisense DNA | <molecular biology> A synthetic DNA strand that is complementary to a particular strand of target DNA with a complementary sequence of bases. This results in preventing expression of the gene encoded. These proteins can be used to selectively turn off production of certain proteins or block viral genetic instructions, by marking them for destruction by cellular enzymes, in order to prevent the building of new virus or the infection of new cells. (14 Nov 1997) |
| apurinic DNA | <molecular biology> A DNA molecule that has lost adenine and guanine, its purine bases. Apurinic DNA can be produced by treating the DNA with acid. (09 Oct 1997) |
| ATP-dependent DNA strand transferase | <enzyme> From human cell nuclei; catalyses strand exchange between homologous DNA sequences; magnesium dependent, requires ATP hydrolysis Registry number: EC 2.7.7.- Synonym: ATP-dep-DNA-str trnsfase (26 Jun 1999) |
| bacteriophage T7 induced DNA polymerase | <enzyme> Complex of two proteins, phage gene 5 protein and E coli thioredoxin Registry number: EC 2.7.7.- Synonym: t7 phage DNA polymerase, sequenase, t7 DNA polymerase, thermo sequenase (26 Jun 1999) |
| base in DNA | A unit of the DNA. There are 4 bases: adenine (A), guanine (G), thymine (T), and cytosine (C). The sequence of bases (for example, CAG) is the genetic code. (12 Dec 1998) |