Brown BIOL1220:Notebook/SynBio in Theory and Practice/Genes/ADAR: Difference between revisions
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=== Why edit pre-mRNA? === | === Why edit pre-mRNA? === | ||
* | * To increase genetic diversity through changes in the transcriptome. For an example of this, see [[ADAR Functions in Receptors|below]]. | ||
=== ADAR Functions in Receptors === | |||
* Deamination by editing in pre-mRNAs encodes a variety of subunits of ionotropic glutamate receptors (GluRs). | |||
* Editing at the Q/R site of the GluR2 (GluRB) subunit of AMPA receptors changes a Gln codon CAG to an Arg codon CIG, which makes the heteromeric receptor impermeable to Ca2+ ions. | |||
* Editing of 5-HT2C subtype serotonin receptor mRNA results in receptor isoforms with reduced G-protein coupling efficiency (reviewed by Gerber and Keller, 2001). | |||
Revision as of 21:46, 22 February 2009
Adenosine Deaminases that act on RNA (ADARs)
The Functions of the ADAR Family
- Three members of this deaminase family are known: ADAR 1, ADAR 2, and ADAR 3 that share a common modular domain structure.
- ADARs modify pre-mRNA and recognize structural determinants in the RNA.
- In mice, the editosomes with ADAR proteins require some cis-acting elements like an intronic 'editing-site complementary sequence (ECS)'. Although evolutionarily conserved, the actual role of ECS is not yet elucidated in humans. A representation of the editing complex is shown below.
- The deamination of adenosines (A) to inosine (I) is the most common editing event.
Why edit pre-mRNA?
- To increase genetic diversity through changes in the transcriptome. For an example of this, see below.
ADAR Functions in Receptors
- Deamination by editing in pre-mRNAs encodes a variety of subunits of ionotropic glutamate receptors (GluRs).
- Editing at the Q/R site of the GluR2 (GluRB) subunit of AMPA receptors changes a Gln codon CAG to an Arg codon CIG, which makes the heteromeric receptor impermeable to Ca2+ ions.
- Editing of 5-HT2C subtype serotonin receptor mRNA results in receptor isoforms with reduced G-protein coupling efficiency (reviewed by Gerber and Keller, 2001).
