RNA editing

RNA editing is a molecular process through which some cells can make discrete changes to specific nucleotide sequences within an RNA molecule after it has been generated by RNA polymerase. RNA editing involves the alteration of the sequence of the primary RNA transcript to change its coding potential. These changes can lead to proteins that differ in amino acid sequence from the gene that encodes them.

Mechanisms of RNA Editing

RNA editing can occur in both the nucleus and cytoplasm. It can affect the function of the RNA molecule in a variety of ways, including altering codon identity, splicing patterns, and mRNA stability.

There are two types of RNA editing:

1. Substitution editing: This involves the alteration of individual nucleotides. This can be achieved through the deletion or insertion of specific bases or through the conversion of one base to another.
2. Insertion/deletion editing: This involves the addition or removal of nucleotides from the RNA molecule. This type of editing is common in mitochondria and chloroplasts.

Biological Significance of RNA Editing

RNA editing plays a crucial role in the gene expression process. It can alter the protein produced by a gene, allowing organisms to generate protein diversity from a limited number of genes. RNA editing can also regulate the function of non-coding RNAs, such as microRNAs and long non-coding RNAs.

In humans, RNA editing is carried out by a family of enzymes known as adenosine deaminases acting on RNA (ADARs). Dysregulation of RNA editing has been linked to various diseases, including cancer, neurological disorders, and autoimmune diseases.

RNA Editing in Disease

Abnormal RNA editing has been implicated in a number of diseases. For example, over-editing of the glutamate receptor gene can lead to neuronal death and is associated with neurodegenerative diseases such as Alzheimer's disease. On the other hand, under-editing of certain RNA molecules can lead to the development of cancer.

See Also

• DNA editing
• Epigenetics
• Post-transcriptional modification