| leukaemia, myeloid | Form of leukaemia characterised by an uncontrolled proliferation of the myeloid lineage and their precursors in the bone marrow and other sites. (12 Dec 1998) |
|---|---|
| amphoteric element | An element one or more of whose oxides unite with water to form hydroxides that may act as acids or as bases (e.g., aluminum). (05 Mar 2000) |
| anatomical element | Any anatomical unit, such as a cell. Synonym: morphologic element. (05 Mar 2000) |
| vessel element | Part of a xylem vessel in a higher plant, arising from a single cell. The end walls are perforated and may completely disappear, giving rise to a continuous tube. The remaining walls are thickened and lignified and there is no protoplast. (18 Nov 1997) |
| volume element | See: voxel. (05 Mar 2000) |
| P element | <molecular biology> A class of Drosophila transposon, widely used as a vector for reporter genes, for efficient germ line transformation and for enhancer trap or insertional mutagenesis studies. (18 Nov 1997) |
| mobile genetic element | <molecular biology> Small, mobile DNA sequences that can replicate and insert copies at random sites within chromosomes. They have nearly identical sequences at each end, oppositely oriented (inverted) repeats and code for the enzyme, transposase, that catalyses their insertion. Bacteria have two types of transposon, simple transposons that have only the genes needed for insertion and complex transposons that contain genes in addition to those needed for insertion. Eukaryotes contain two classes of mobile genetic elements, the first are like bacterial transposons in that DNA sequences move directly. The second class (retrotransposons) move by producing RNA that is transcribed, by reverse transcriptase, into DNA which is then inserted at a new site. (13 Nov 1997) |
| picture element | <microscopy> Any segment of a video scan line whose dimension along the line is equal to the line spacing. (05 Aug 1998) |
| morphologic element | Any anatomical unit, such as a cell. Synonym: morphologic element. (05 Mar 2000) |
| control element | Generic term for a region of DNA, such as a promoter or enhancer adjacent to (or within) a gene that allows the regulation of gene expression by the binding of transcription factors. (18 Nov 1997) |
| controlling element | A transposon which, when inserted into or removed from a gene, breaks the chromosome and/or causes mutations. (09 Oct 1997) |
| copia element | A group of transposons whose base sequences are closely related to each other, found in the genome of the fruit fly genus Drosophila. (09 Oct 1997) |
| polarizing element | <microscopy> A general term for a device for producing or analysing plane-polarized light. It may be a Nicol prism, some other form of calcite prism, a reflecting surface, or a polarizing filter. (05 Aug 1998) |
| heat-shock response element | <cell biology, protein> The nucleotide sequence, CNNGAANNTCCNG, which is in the promoter region of the heat-shock genes. When the animal is exposed to certain types of stress such as a sudden rise in temperature, the first thing that happens to activate these genes is the binding of the HSE by a transcriptional enhancer protein. (09 Oct 1997) |
| serum response element | Dyad symmetry element bound by serum response factor to control the expression of c fos. (18 Nov 1997) |