| ANK repeat | <molecular biology> Amino acid motif found in diverse proteins including ankyrins (hence the name), the notch product, transcriptional regulators, cell cycle regulatory proteins and a toxin produced by the black widow spider. The motif is about 33 amino acids long and is generally found as a tandem array of 2-7 repeats, though ankyrins contain 24 repeats. Their role is not established, but they may be involved in protein protein binding. (18 Nov 1997) |
|---|---|
| ankyrin repeat | Protein domains that contain 33-amino acid long sequences that often occur in tandem arrays. This repeating sequence of 33-amino acids was discovered in ankyrin and is involved in interaction with the anion exchanger (band 3 protein) and may perform a role in molecular recognition in diverse proteins. (12 Dec 1998) |
| cesarean section, repeat | Extraction of the foetus by abdominal hysterotomy anytime following a previous cesarean. (12 Dec 1998) |
| heptad repeat | <molecular biology> A heptad repeat is a type of tandem repeat sequence. It is a sequence of seven amino acids which is repeated multiple times in a row within certain proteins (the intermediate filament proteins) of nearly every animal in the animal kingdom. (09 Oct 1997) |
| HIV long-terminal repeat | Regulatory sequences important for viral replication that are located on each end of the HIV genome. The ltr includes the HIV enhancer, promoter, and other sequences. Specific regions in the ltr include the negative regulatory element (nre), nf-kappa b binding sites , sp1 binding sites, tata box, and trans-acting responsive element (tar). The binding of both cellular and viral proteins to these regions regulates HIV transcription. (12 Dec 1998) |
| direct terminal repeat | A particular sequence of nucleotides which appears on both ends of a DNA or RNA molecule. (09 Oct 1997) |
| inverted repeat | Either of two copies of a DNA sequence (such as those foundat oppositeends of a transposon) whichoccur in identical but inverted form. (09 Oct 1997) |
| tandem repeat | <molecular biology> Copies of genes repeated one after another along a chromosome: for example the 40S rRNA genes in somatic cells of toads, of which there are about 500 copies. (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) |
| tandem repeat sequences | Multiple copies of the same DNA base sequence on a chromosome; used as a marker in physical mapping of the chromosome. (12 Dec 1998) |
| trinucleotide repeat | <molecular biology> Repetitive part of a genome that may form part of the coding sequence of a gene. The length of such repeats is frequently polymorphic and unstably amplified repeats appear to be the major cause of such genetic diseases as Huntington disease, fragile X syndrome, spinobulbar muscular atrophy and myotonic dystrophy. (18 Nov 1997) |
| long-terminal repeat | <molecular biology> Identical DNA sequences, several hundred nucleotides long, found at either end of transposons and the proviral DNA, formed by reverse transcription of retroviral RNA. They are thought to have an essential role in integrating the transposon or provirus into the host DNA. Long terminal repeats have inverted repeats, that is, sequences close to either end are identical when read in opposite directions. In proviruses the upstream long-terminal repeat acts as a promoter and enhancer and the downstream long-terminal repeat as a polyadenylation site. Acronym: LTR (15 Nov 1997) |
| long terminal repeat sequences | Regions of the RNA genome associated with regulation, integration, and expression of retroviruses. (05 Mar 2000) |
| absolute unit | A unit whose value is constant regardless of place or time and not derived from dependent on gravitation. (05 Mar 2000) |
| alexin unit | The smallest amount (highest dilution) of complement that will cause haemolysis of a unit of red blood cells in the presence of a haemolysin unit. Synonym: alexin unit. (05 Mar 2000) |