Question

What is meant by capping and tailing?

Answer 1

The premature form of mRNA which is produced in the humans is called as heterogenous RNA (hnRNA). This RNA molecule undergoes modification like the splicing in which the introns are removed and the exons are ligated. There are other modifications like capping and tailing. There is an addition of 7-methylguanylate at the 5' end of the mRNA. This process is known as the capping of the mRNA. At the 3' end of the mRNA, there is an addition of a chain of adenine nucleotides. This is known as the poly-A tail or the tailing mechanism. These are the modifications to protect the mRNA from degradation by nucleases.