The 5'cap of RNA is required for the ?

    A) stability of RNA only

    B) transport of RNA only

    C) stability and transport of RNA

    D) methylation of RNA only

    E) none of these

 Ans: C) stability and transport of RNA

          5' capping: A key step in RNA processing

• After transcription, the phosphate group at the 5' end is removed and replaced by a guanine  residue by guanosyl transferase and further methylated to form 7-methyl guanosine cap (m7G).
• 5' cap protects the 5' end of mRNA against ribonuclease degradation and also functions in protein synthesis initiation.
• This stabilizes pre -mRNA and is important for the stability of mature mRNA. It also important in binding to the nuclear matrix and transport of mRNA out of the nucleus.