User:Johno4302/ApoB mRNA editing

The pre-mRNA of GluR-6(GRIK2) is subjected to RNA Editing.The GluR-6 protein functions as a subunit of Kainate receptors.

EDITING SITES
The pre-mRNA of GLUR-6 is edited at three positions at amino acid positions 567, 571, and 621..The first is the Q/R posistion so called as editing results in an codon change from a glutamine codon (Q) to an arginine codon(R).The Q/R editing site is also observed  in glutamte recptor GluR-2 and GluR-5.GluR-6 is also edited at I/V and Y/C sites.These occur within the first and second intracellular domains.Rna editing is thought to alter the function and structure of the receptor complex. RNA fold programme characterised a putative double stranded RNA(dsRNA) conformation around the Q/R site of the GluR-6 pre-mRNA.The possible editing complementary sequence was observed 1.9 kb downstream from the editing site within intron 12.(herb Reference)

FUNCTION OF EDITING
The on edited transcript has a glutamine at position 621.This residue determines the low calcium permeability of the channel.In edited transcripts the residue at this position is arginine which determines a higher calcium permeability especially if editing has also occurred at positions 567 and 571.

Frequency of editing
The receptor is 90% in all grey matter structures.In white matter of the brain the receptor is in edited form in just 10% of cases.