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An example of upregulation is the response of liver cells exposed to such xenobiotic molecules as dioxin. In this situation, the cells increase their production of cytochrome P450 enzymes, which in turn increases degradation of these dioxin molecules. Downregulation or upregulation of an RNA or protein may also arise by an epigenetic alteration ...
Up-regulation is a process which occurs within a cell triggered by a signal (originating internal or external to the cell), which results in increased expression of one or more genes and as a result the proteins encoded by those genes. Conversely, down-regulation is a process resulting in decreased gene and corresponding protein expression.
The genomic DNA of eukaryotic cells is wrapped around special protein molecules known as histones. The complexes formed by the looping of the DNA are known as chromatin . The basic structural unit of chromatin is the nucleosome : this consists of the core octamer of histones (H2A, H2B, H3 and H4) as well as a linker histone and about 180 base ...
These substances can disrupt cell membranes, activate cell receptors, aggregate or degrade certain proteins, or disrupt the mucosal surface layer. The immune system often responds to these substances with reactions that lead to the removal of an irritant substance from the body, such as itching , coughing , sneezing , or vomiting . [ 16 ]
It is widely used for the specific uptake of certain substances required by the cell (examples include LDL via the LDL receptor or iron via transferrin). The role of receptor-mediated endocytosis is well recognized to up take downregulation of transmembrane signal transduction but can also promote sustained signal transduction. [3]
Cells can communicate with each other by releasing molecules that produce signaling cascades within another receptive cell. If the signal requires upregulation or downregulation of genes in the recipient cell, often transcription factors will be downstream in the signaling cascade. [27]
An example would be the coagulation ... which leads to downregulation of adhesion. ... The differentiation of B cells to plasma cells is also an example of a signal ...
After being produced, the stability and distribution of the different transcripts is regulated (post-transcriptional regulation) by means of RNA binding protein (RBP) that control the various steps and rates controlling events such as alternative splicing, nuclear degradation (), processing, nuclear export (three alternative pathways), sequestration in P-bodies for storage or degradation and ...