Gene silencing is a general term describing epigenetic processes of gene regulation. The term gene silencing is generally used to describe the "switching off" of a gene by a mechanism other than genetic modification. That is, a gene which would be expressed ("turned on") under normal circumstances is switched off by machinery in the cell. Gene silencing occurs when RNA is unable to make a protein during translation.
Genes are regulated at either the transcriptional or post-transcriptional level.
Transcriptional gene silencing is the result of histone modifications, creating an environment of heterochromatin around a gene that makes it inaccessible to transcriptional machinery (RNA polymerase, transcription factors, etc.).
Post-transcriptional gene silencing is the result of mRNA of a particular gene being destroyed or blocked. The destruction of the mRNA prevents translation to form an active gene product (in most cases, a protein). A common mechanism of post-transcriptional gene silencing is RNAi.
Both transcriptional and post-transcriptional gene silencing are used to regulate endogenous genes. Mechanisms of gene silencing also protect the organism's genome from transposons and viruses. Gene silencing thus may be part of an ancient immune system protecting from such infectious DNA elements.
Genes may be silenced by DNA methylation during meiosis, as in the filamentous fungus Neurospora crassa.
Other articles related to "gene silencing, gene, silencing":
... Gene silencing aims to reduce the production of the mutant protein, since HD is caused by a single dominant gene encoding a toxic protein ... Gene silencing experiments in mouse models have shown that when the expression of mHtt is reduced, symptoms improve ... Safety of non-allele specific RNAi and ASO gene silencing has now been demonstrated in mice and the large, human-like brains of primates ...
... Gene silencing aims to reduce the production of the mutant protein, since HD is caused by a single dominant gene encoding a toxic protein ... Gene silencing experiments in mouse models have shown that when the expression of mHtt is reduced, symptoms improve ... Safety of gene silencing has now been demonstrated in the large, human-like brains of primates ...
... more terms related to specific topics of gene silencing Transcriptional Gene Silencing Genomic Imprinting Paramutation Transposon silencing Transgene silencing Transcriptional ...
... Gene silencing at this location depends on components of the RNAi pathway ... Double-stranded RNA is believed to result in silencing of the region through a series of steps ... two RNAi complexes, the RNAi-induced transcriptional gene silencing (RITS) complex and the RNA-directed RNA polymerase complex (RDRC), are part of an RNAi machinery ...
Famous quotes containing the word silencing:
“The peculiar evil of silencing the expression of an opinion is, that it is robbing the human race; posterity as well as the existing generation; those who dissent from the opinion, still more than those who hold it. If the opinion is right, they are deprived of the opportunity of exchanging error for truth: if wrong, they lose, what is almost as great a benefit, the clearer perception and livelier impression of truth, produced by its collision with error.”
—John Stuart Mill (18061873)