RNA editing

Free life science studymaterial. Online Free life science study material. Hi RNA editing. This process is required to get variety of protein from single gene or DNA sequence. Any change such as addition, deletion or substitution in RNA can be achieved for getting desired protein from single gene. It always takes place in eukaryotes as procaryotes do not have introns. First observed in Trypanosoma gamibiense. Some times there is gap in DNA sequence it is also countere by gRNA or RNA editing mechanism. Mechanism pre mRNA is acted upon by guide/gi RNA. Editing is directional in 3'--5' direction. gRNA has stretch of A in between its sequence and this gRNA pairs with the targetRNA. The stretch of A does not pair with the target strand hence forms loop in between. Endonuclease acts on target RNA and causes a nick in target strand opposite to the AAAA of gRNA. (Consult diagram from book)After nick formation the loop in gRNA stretch and dUTP adds UUU opposite to AAAA in target RNA by thr help of TdT or terminal deoxynucleotidyl transferase. The gap is filled by ligase. The gRNA only adds UUU not any other nucleotide. Free life science studymaterial.