Substitution RNA editing is known to involve either C-to-U or A-to-I conversions. What common chemical event accounts for each?

Verified step by step guidance

1. Understand that substitution RNA editing involves the conversion of one nucleotide to another, specifically C-to-U (cytidine to uridine) and A-to-I (adenosine to inosine).
2. Recognize that these conversions are catalyzed by specific enzymes: cytidine deaminase for C-to-U and adenosine deaminase acting on RNA (ADAR) for A-to-I.
3. Identify the common chemical event in both conversions: deamination, which is the removal of an amino group from the nucleotide base.
4. In C-to-U conversion, the cytidine deaminase enzyme removes an amino group from cytidine, converting it into uridine.
5. In A-to-I conversion, the ADAR enzyme removes an amino group from adenosine, converting it into inosine, which is read as guanosine by the cellular machinery.

Key Concepts

RNA Editing

RNA editing is a molecular process through which the nucleotide sequence of an RNA molecule is altered after transcription. This modification can lead to changes in the protein that is produced, affecting its function. Substitution editing, specifically, involves the conversion of one nucleotide to another, such as C-to-U or A-to-I, which can significantly impact gene expression and protein diversity.

C-to-U Conversion

C-to-U conversion is a specific type of RNA editing where cytidine (C) is deaminated to uridine (U). This reaction is catalyzed by enzymes known as cytidine deaminases. The resulting change can affect the coding potential of the RNA, potentially altering the amino acid sequence of the resulting protein, which can have functional implications in various biological processes.

A-to-I Conversion

A-to-I conversion refers to the editing process where adenosine (A) is converted to inosine (I) through the action of adenosine deaminases. Inosine is interpreted as guanosine (G) during translation, which can lead to changes in the protein sequence. This type of editing is particularly important in regulating gene expression and can influence the stability and function of RNA molecules.