Gene silencing is the capacity of a cell to restrict or suppress the manifestation of a gene.
Just like you reduce the volume of a song you are listening to minimise the sound, gene silencing limits the capabilities of a gene.
Gene silencing is sometimes confused with gene knockout which is the complete removal of the genome of an organism.
It started in the late 1990s when scientists Andrew Fire and Greg Meillo were looking for ways to develop treatments for Alzheimer’s disease. In genetic engineering, gene silencing is used to proffer solutions for the treatment of diseases. It also occurs naturally in the body to control the actions of a gene.
There are transportable genetic elements in gene silencing that move from one position to another. They are called transposons and are responsible for the movement of genetic elements in a gene.
Techniques of Gene Silencing
Gene silencing takes place when interruptions are experienced in the transcription and translation process. In transcription, the DNA functions as a template for the formation of RNA strands while in translation, the messenger RNA reacts with proteins. Both processes are useful in the two types of gene silencing discussed below.
There are two types of gene silencing: transcriptional gene silencing and RNA interference gene silencing.
Transcriptional gene silencing
In transcriptional gene silencing, genes are suppressed due to behavioural and environmental factors. This results in a temporary change in the DNA sequence. Examples of such factors are DNA Methylation, Acetylation, and Histone Methylation.
DNA methylation is the most common form of transcriptional gene silencing and it is the addition of methyl to the CpG area of the DNA which makes it dormant.
RNA interference gene silencing
In RNA interference gene silencing, gene silencing is done by small interfering RNA (siRNA) and micro RNA (miRNA).
The siRNA performs gene silencing by breaking the mRNA transcripts before translation while the miRNA performs gene silencing by joining with the target messenger RNA while preventing translation.
Applications of Gene Silencing
- Gene silencing is used in the treatment of some diseases such as asthma, hepatitis B and C. Trails are currently ongoing to use gene silencing in the treatment of HIV.
- Gene silencing is used to analyse genes associated with cancer and other genetic disorders.
- Gene silencing is used in genetic engineering for producing genetically modified organisms.
- It limits the manifestation of some cancer-causing genes.
- It is utilised in the food processing industries.
- Gene silencing is used for building a plant’s resistance to certain diseases. Plants like tomatoes, rice, and wheat have experienced tremendous growth in being resistant to pests.
- Gene silencing speeds up the manufacturing of proteins in protein expression systems.
- It is used to enhance the grades of crops in agriculture. This is done by weakening the production of toxins in certain crops.
- It is utilised for the research and production of new drugs.
Gene silencing has proved useful in agriculture, biomedical, and genetic engineering fields. It has a long road to go through in the future as research on its numerous benefits in genetic engineering is still ongoing. More discoveries are sure to come in later years.