5'-Capping on mRNA occurs shortly after the transcription initiation when the transcripts are about 20-25 nucleotides in length. During the capping step of mRNA processing, 7-methyl guanosine is added at the 5' end of the mRNA. The 5' cap protects the 5' end of the mRNA from degradation and failure to cap or loss of cap leads to rapid breakdown of the RNA by nucleases. In the cytoplasm, The 5' cap helps to position the mRNA correctly on the ribosomes during protein synthesis. Apart from, these two functions, the 5' cap also helps in exports of mRNA from nucleus to the cytoplasm. Cap binding complex (CBC) that associated with the 5' cap leads the way through the nuclear pore complex to exports the mRNA from nucleus to the cytoplasm.