|
|
Polyadenylation - Polyadenylation is the addition of adenylate residues at the 3' end to form a long chain of poly (A) consisting of 180-200 nucleotides. This takes place by the action of poly (A) synthetase. Polyadenylation may take place immediately after transcription, or after cleavage of transcripts.
Poly (A) may have some role in stabilizing the mRNA. mRNAs deadenylated by enzymes and then injected into amphibian oocytes are more rapidly destroyed then adenylated mRNAs. Some mRNA types, e.g. his tore mRNA, are directly transcribed from repetitive DNA sequences without the formation of precursor hnRNA, and do not undergo polyadenylation.
|
