Methyl guanosine triphosphate is added at 5' end of hn-RNA in a process of

Primary transcript is non functional due to presence of introns . primary transcript undergoes processing to form functional mRNA . Processing includes thee steps . 1) capping 2) tailing  3) splicing .In capping, unusual nucleotide (methyl guanosine triphosphate) is added to 5' end of hn-RNA and forms cap.