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 are regulated at either the transcriptional or
post-transcriptional level. 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.
|