cytidine to uridine editing

Definition

Target type: biologicalprocess

The conversion of a cytosine residue to uridine in an RNA molecule by deamination. [PMID:11092837]

Cytidine to uridine editing, also known as C-to-U editing, is a post-transcriptional modification of RNA that involves the conversion of cytidine (C) nucleotides to uridine (U) nucleotides. This process is catalyzed by a family of enzymes called adenosine deaminases acting on RNA (ADARs). ADARs are highly specific enzymes that recognize double-stranded RNA (dsRNA) structures and deaminate adenosine (A) residues to inosine (I) within these structures. However, through a process called "substrate mimicry," some ADARs can bind and edit single-stranded RNA, including pre-mRNAs.

During C-to-U editing, ADARs recognize specific sequence motifs within dsRNA. These motifs often include a cytidine residue flanked by a purine base on one side and a pyrimidine base on the other. The ADAR enzyme then binds to the dsRNA and uses its catalytic domain to deaminate the cytidine base, converting it to uridine. This conversion can result in significant changes to the RNA sequence and, consequently, to the protein that is encoded by the mRNA.

C-to-U editing plays a critical role in regulating gene expression and cellular function. It can affect mRNA splicing, translation, and stability. It can also influence the activity of microRNAs, small non-coding RNAs that regulate gene expression.

Examples of C-to-U editing include:

1. **Editing of the GluR2 mRNA:** This mRNA encodes a subunit of the AMPA glutamate receptor, a key component of synaptic transmission in the brain. C-to-U editing of the GluR2 mRNA results in the substitution of arginine with glutamine at a specific position in the protein. This editing event is essential for the proper function of the AMPA receptor and plays a critical role in neuronal plasticity.

2. **Editing of apolipoprotein B (ApoB) mRNA:** This mRNA encodes a protein involved in lipid transport. C-to-U editing of the ApoB mRNA results in a premature stop codon, leading to the production of a truncated protein called ApoB48. This editing event is important for regulating lipid metabolism.

3. **Editing of the serotonin receptor 5-HT2C mRNA:** This mRNA encodes a serotonin receptor involved in mood, appetite, and sleep regulation. C-to-U editing of the 5-HT2C mRNA can affect the receptor's sensitivity to serotonin and has been implicated in various neurological disorders.

In summary, C-to-U editing is a crucial post-transcriptional modification that plays a vital role in regulating gene expression and cellular function. It can affect various cellular processes, including mRNA splicing, translation, and stability, and has been implicated in several neurological disorders. The discovery and study of C-to-U editing have provided important insights into the complexity of gene regulation and the diversity of RNA modifications.'
"

Proteins (1)

Compounds (33)